When it comes to horrific school attacks and shootings, "See something, say something, do something" is apparently a policy that really does save innocent lives.

Police, schools and parents are stopping school attacks across America by taking the threats seriously, reporting them and quickly arresting the students before there's ever a massacre.

(See the rapidly growing list of recently thwarted school attacks at the end of this article.)

In the case of Nikolas Cruz, the shooter who opened fire on students at a Florida high school on Valentine's Day and killed 17 people, reports about his disturbing behavior apparently came flooding in to authorities. Cruz's friends saw something. They said something. But authorities apparently didn't do anything.

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Ariana Lopez, a former friend of Cruz, said she told school authorities "multiple" times in 2016 and 2017 about Cruz's "disturbing" behavior.

"He used to sell knives out of his lunchbox, which I thought was like insane because you can't have knives ... [in] a school," she told ABC's "Good Morning America" Tuesday. "He would talk about how he sympathized with Syrian terrorists and how people who opposed them should be killed."

Lopez also said Cruz would behave violently toward his ex-girlfriend, toward her and toward her friends.

"He talked about killing our parents, our friends, boyfriends and girlfriends," she said. "He would hit [his ex-girlfriend]. He would threaten her. He would threaten her family and her friends, for talking to other guys."

Lopez said she and her classmates weren't surprised to learn the shooter was Cruz: "Even before they announced that he was the shooter, we all knew it was Nik. He was the only person that we could think of that would do something like this because it was obvious that he had the power to do this."

Cruz was also reported to the FBI and police, according to reports. The FBI failed to act on a tip that Cruz sought to "kill people" and there was "potential of him conducting a school shooting." The FBI received a phone call on Jan. 5 from a person who was seeking to report Cruz's disturbing behavior and social media posts. The FBI admitted it didn't follow protocols and assess the situation as a threat. Attorney General Jeff Sessions has called for an "immediate review" of the case.

"It is now clear that the warning signs were there and tips to the FBI were missed," Sessions said Friday. "We see the tragic consequences of those failures."

Cruz also had dozens of run-ins with police dating back to 2010. Broward County Sheriff Scott Israel told Fox News there were "20 calls for services in the last few years." Cruz was never arrested. He had reportedly thrown things, fought with his mother, acted out in violence, talked about hurting himself and said he would buy a gun. In 2017, Cruz was expelled from school for "disciplinary problems." One report indicated that bullets were found in his backpack.

A YouTube user in Mississippi, Ben Bennight, said he called the FBI last September to report that a person called "nikolas cruz" had written, "I'm going to be a professional school shooter" in the comments section under a video. FBI agents visited Bennight following the tip, but nothing came of the report.

But because he had no criminal record that prevented him from doing so, Cruz was able to legally purchase the AR-15 rifle he used to murder 17 people on Feb. 14.

In just the last several days and weeks, authorities have become hyper-vigilant in responding to threats of school shootings. Now police are cracking down, arresting students who threaten the lives of other students, teachers and administrators.

Not every case involved firearms. Some students possessed knives. Others included a crossbow and machetes.

WND has compiled the following list of recent school attacks that were stopped before they ever happened – thanks to quick actions of police, school officials, concerned parents and students who are boldly speaking up and taking action to prevent the loss of another innocent life.

Alabama

Foley Middle School in Foley: Police arrested a 14-year-old male student who reportedly threatened to "shoot up the school" on Feb. 20.

Police say the student told someone he was "going to shoot up the school by the end of the year."

An individual who knew of the threat informed a school resource officer. The teen was immediately arrested and is being charged with making a terroristic threat.

Police say they haven't found evidence that he intended to follow through with a shooting.

"A lot of what we're hearing is 'Oh it was a joke.' No, it's not a joke. If you do this, we take it seriously and respond accordingly," said Thurston Bullock from the Foley Police Department, Fox 10 reported. "We don't want to see kids mess up their lives because they are joking around. And it's not a joke when we have something as serious as Florida and things like this happening across the nation. It's a serious matter, and we're going to treat it accordingly."

Arkansas

Fayetteville High School in Fayetteville: A student was arrested Feb. 16 after the individual made a Snapchat post threatening to "shoot up the high school like they did in Florida." The student, who claimed the post was a joke, was arrested due to the serious nature of the threat. The individual is being held at the Washington County Juvenile Detention Center.

Fayetteville Public Schools Superintendent Matthew Wendt said in a statement: "When we are made aware of any type of threat, we work together with the police to act swiftly and decisively. We look forward to a regular day of school today."

California

Pixley Middle School in Pixley: A 13-year-old boy was arrested Feb. 16 after he threatened to "shoot up" the school in a post he made online.

As soon as school administrators learned who the boy was, they called police.

Detectives searched the boy's home and found a handgun and four rifles.

"There couldn’t be a more appropriate time to remind people that, if you see something suspicious or that seems off, say something. It is so important," said Sheriff Mike Boudreaux, according to the Visalia Times-Delta. "You can do it anonymously. Our deputies can't look into a situation if they know nothing about it."

Cambridge High School in Fresno: Asante Freeman, 18, was arrested Feb. 16 after he reportedly threatened to bring an AR-15 rifle to school in Facebook posts.

His post stated, "Finna cop a ar-15 see y'all at Cambridge tomorrow."

Freeman, a former student, graduated from Cambridge last year.

Several of Freeman's Facebook friends warned him to stop making the posts. They told him police were monitoring social media. But Freeman was defiant.

"They're not stopping s--t," he wrote.

His friends told him his statements weren't funny.

But Freeman continued anyway: "People get killed every day all kinds of ways. If they don't get shot at school could have been on the streets it's life can't get sad of everything that's f---ed up in this world."

Connecticut

Kennedy High School in Waterbury: Police arrested Christopher Roman, 20, on Feb. 20. A 17-year-old student at Kennedy High School had told police Roman called him on FaceTime and threatened to "shoot up" the school.

The student said Roman showed a black revolver in the calls.

Roman has been charged with first-degree breach of peace, first-degree threatening, brandishing a facsimile firearm and interference. School was expected to be back in session Wednesday.

Florida

Mainland High School in Daytona Beach: Officers with the Daytona beach Police Department arrested a 20-year-old man on Feb. 15 who had threatened his classmates with violence and made "other disturbing general comments."

Palm Beach Lakes High School in West Palm Beach: A student brought two guns to his high-school campus on Feb. 15 and was quickly arrested after police received an anonymous tip. When authorities approached the student, the person fled. The school was put on lockdown. Principal David Alfonso told parents: "The police recovered two guns in the same vicinity that the student fled. The student was arrested by our campus police officers and now faces expulsion as defined in our student code of conduct."

Palmetto Ridge High School in Naples: On Feb. 19, police arrested 18-year-old student Benjamin Mendoza after they received a tip that he had brought a gas mask and a knife to school on Feb. 15 and had made "disturbing comments about the Las Vegas mass shooting." Authorities found he had a knife in his possession. They also discovered a note that said "shoot up school" and "school shoot animae dead" along with a list of students' names. The student's list also included a drawing of another student riddled with bullet holes. The words "Dead haha dead" were scribbled on the back of the paper. Police also found a map of the campus in his possession.

Mendoza has been charged with possession of a weapon on school grounds and disruption of a school function.

Middleton High School in Tampa: A suspended 15-year-old student threatened his school when he was told to leave. Police arrested the student on Feb. 19 after he stated: "I'm going to come back tomorrow and shoot this b--ch up. I don't give a f--k. I'm going to f---k this school up." The student was charged with making a false report concerning the use of a firearm in a violent manner.

Robinson High School in Tampa: Police arrested a student who threatened a teacher and promised to "shoot up the school." Police say the student said, "If you do not change my grade, I will shoot up the school." The student was charged with making a false report concerning the use of a firearm in a violent manner.

Wakulla High School in Crawfordville: Police arrested Kane Watson, 18, who surrendered his AR-15 style rifle to authorities and has been booked into Wakulla County jail.

Watson reportedly posted a threatening video to Snapchat warning students, "Don't go to school."

The teen has been charged with written threats to kill or do bodily injury and false report concerning planting a bomb, an explosive or a weapon of mass destruction or concerning the use of firearms in a violent manner, according to the Tallahassee Democrat.

"The video showed a person's hands opening a case containing the rifle, which was later identified as a Spike's SL 15 Tactical Rifle," the Democrat reported. "The video shows the rifle being removed from the case and loaded with a magazine. The rifle is then picked up by the subject and displayed a caption underneath that read, 'Do not go to school.'"

Deputies and detectives reportedly arrived at Watson's home just 45 minutes after they received a complaint about his disturbing post.

Watson claimed his post was just a joke.

"He said it was an attempt at releasing stress through humor," said Wakulla County Sheriff's Office spokesman Lt. Chris Savary. "We can only take him at his word, but we would treat any threat like this as credible."

Georgia

Plano West Senior High School in Plano: Police arrested a 16-year-old student on Feb. 15 after they received an anonymous Campus Crime Stoppers tip and learned that the student had brought a handgun to campus.

Indiana

Michigan City High School in Michigan City: Police arrested a 16-year-old student on a felony intimidation charge after he wrote in a social media post that a shooting would happen at the school on Feb. 13. His post also included a photo of a gun.

Within four hours, police found the teen and took him into custody. He may be expelled from the school.

"Given today's climate throughout the nation, we as law enforcement take these threats very seriously," said Michigan City Police Chief Mark Swistek.

Columbus East High School in Columbus: A student was arrested for threatening violence against his school on Feb. 20. He's expected to face felony intimidation charges for sending the threatening message to several students on Snapchat.

When parents heard about the threat, they began arriving at the high school to pick up their children.

Maryland

Clarksburg High School in Clarksburg: Police arrested Alwin Chen, 18, who took a loaded handgun and knife to school on Feb. 15. The gun was in his backpack, and the knife was in his pocket.

At his home, Chen also had an AR-15 rifle, a tactical vest, inert grenades, handguns and a detonator.

"Multiple people, including the crisis intervention team and the court diagnostic team that screened him before before the bond review, were all making recommendations that there be a psychiatric evaluation for dangerousness. They did in fact order that evaluation and there is no court date yet set in this matter," Montgomery County State's Attorney John McCarthy said Tuesday, Fox-5 DC reported.

According to prosecutors, Chen also had a list of grievances against other students in his possession when he was taken into custody. He told police he brought the gun to school to protect himself from bullies. Apparently, it wasn't the first time Chen had brought a gun to school.

Michigan

Brethren High School in Brethren: Police arrested a 17-year-old student on Feb. 19 for making a terroristic threat.

The teen is accused of making a verbal threat to shoot up the Brethren High School. Several students heard the threat and reported it to the principal. When police confronted the teen, he claimed he was "just joking." Authorities confiscated an AR-15 rifle, which belongs to his parents, and a cell phone from the teen's home. The teen is now in Manistee County Jail.

North Carolina

South Brunswick Middle School in Southport: A 12-year-old student was taken into police custody Feb. 20 after admitting he threatened to take a gun to school and shoot people.

Students who heard the threats alerted the school. The school notified the school resource officer. Police do not believe there's a threat to students.

The boy was suspended and charged with "making a false report concerning mass violence on educational property."

Ohio

Wait High School in Toledo: Police arrested 20-year-old Christian Costet on Feb. 19 for threatening a "mass shooting" at the high school.

Costet is accused of posting photos and video on social media, along with threats to carry out the attack.

A concerned parent reported the video and messages to police.

"The Toledo Police Department will not tolerate any threats to the safety of our citizens," said Chief George Kral, according to WTVG-TV 13. "There is no such thing as 'this was just a joke.' With mass shooting incidents increasing exponentially in our country, we will investigate and prosecute every threat to the full extent of the law."

Costet was booked at the Lucas County Jail. He is facing charges of inducing panic, a felony of the second degree.

Jackson Memorial Middle School: A seventh-grade student shot himself in a bathroom at his middle school Feb. 20. Bomb squads swept the school. The boy reportedly had "distractionary type devices" in his backpack used to distract by smoke or sound.

The students has been hospitalized. It's unclear whether the shooting was intentional. The FBI and Ohio's Bureau of Criminal Investigation responded to the scene. Parents rushed to the school, hoping to find their children and take them home.

The school was locked down Tuesday. No one else was injured.

Ellet High School in Akron: On Feb. 20, police arrested a 16-year-old student who threatened to recreate the horrific Florida shooting at his own school.

He posted a message on Snapchat that stated, "I hate Florida, part 2."

The student has been charged with making a terroristic threat.

Akron Police Lt. Rick Edwards told the Akron Beacon Journal that the boy "admitted to making the threat" after "indicating that he was going to shoot up Ellet High School."

Willoughby South High School: Two students, ages 16 and 17, who referenced a school shooting in a social media post have been arrested and charged with inducing panic, marijuana possession and drug paraphernalia possession on Feb. 20.

Parents called the school and police to report the threat. Parents and teachers helped authorities identify the students. Willoughby police and FBI agents took the students into custody.

"As always, the safety of students is our foremost concern," said Willoughby-Eastlake City Schools Superintendent Steve Thompson. "We have many procedures and policies in place to maintain a safe environment for all students."

Pennsylvania

Uniontown Area High School in Uniontown: On Jan. 25, police arrested a 14-year-old student who was threatening to carry out a shooting at his high school the following day. Another student overheard the threats while they were riding a bus and told his parents when he went home. The parents called law-enforcement authorities.

Police found a stash of weapons in the teen's bedroom – one semi-automatic rifle, one shotgun, two lever-action rifles, one revolver, one crossbow, bulk ammunition, throwing knives and two machetes – and learned the suspect planned to target four students.

"The individual also expressed dislike for these four students and his uncle. He indicated it would be extremely easy to sneak a gun into the school in his backpack. He also indicated that he could use a sniper rifle from a distance or a shotgun for mass casualties," Fayette County District Attorney Richard Bower said. "He didn't like them; he just didn't like them."

The teen was charged with terroristic threats, possession of a firearm by a minor and criminal attempt to commit catastrophe.

Parents said the student who reported the threat is a "hero," KDKA-TV 2 reported.

"He's a hero because, if he had not said something or if he just blew it off, who knows what we would have been talking about right now?" parent Roberta Cole asked.

Parent Michael Schock told the station: "The young man is a hero. It takes a lot to stand up and speak."

The district attorney echoed those sentiments: "Quite frankly, the parent and the child who reported this are actually the heroes here. Had they not reported this, there could have been a major catastrophe today at Uniontown High School."

Shade-Central City High School in Cairnbrook: On Feb. 20, Police arrested Jacob Deneen, 18, after he was accused of plotting a mass shooting at his school. Police said he was one of three students who were planning to execute a mass shooting at their graduation this spring. Deneen is faces several charges, including causing or risking a catastrophe and making terroristic threats.

South Carolina

Broome High School in Spartanburg: Police arrested a ninth-grade student on Feb. 15 after he promised "round 2 of Florida tomorrow" in a Snapchat post to students and staff at the high school. The student reportedly included an image of himself posing with a rifle. He's been charged with disturbing schools and the district is attempting to ban him from school grounds.

Texas

Edward S. Marcus High in Flower Mound: Police officers arrested a 16-year-old student who hasn't been named. Other students at the high school reported that the teen had a gun on campus. Police discovered a small-caliber handgun and ammunition in the teen's possession after they pulled the student out of class. The school principal told parents that authorities don't believe the student had planned to hurt anyone with the gun.

Plano West Senior High School in Plano: Police received a tip that a student brought a gun to campus. A school resource officer arrested the student and discovered a handgun. Plano police spokesman David Tilley underscored the importance of the Campus Crime Stopper program there. Tilley said, "The students can make these reports and potentially ... save a major incident from taking place."

Plano Independent School District sent a letter to parents, urging them to pay close attention to their kids' groups of friends and their free-time activities. The letter also asked the parents to be sure their kids are not improperly accessing weapons.

"We share information such as this with families and use this as an opportunity to stress the importance of our students sharing information about anything they see or hear that has the potential to threaten the safety of our campuses, as was done in this case," the letter stated.

South Garland High School in Garland: A 19-year-old student, Kerry Guery, who had two theft warrants was discovered to have an unloaded handgun in his backpack, along with marijuana. Police discovered the firearm after a school resource officer and the high-school principal confronted Guery. The gun's serial number had been scratched off.

Police are uncertain about whether the teen planned to harm students with the gun. Garland police Lt. Pedri Barineau said, "Obviously, we're very cautious in regards to any type of behavior that could lead us to believe some sort of violence could occur."

Nicols Jr. High School in Arlington: A junior-high school student was arrested Feb. 15 after the 13 year old threatened to shoot up his school. The teen reportedly told other students he had a gun. Dallas' KDFW-13 News reported, "[Students] also said he made a specific threat about bringing an AK-47 to school to go after people."

When police confronted the student, he didn't have a gun with him and claimed he was only joking. But he was arrested and charged with making a terroristic threat.

Arlington High School in Arlington: Police arrested two 16-year-old students who threatened to shoot students at their school. They have been charged with making terroristic threats.

Arlington Police Chief Will Johnson tweeted images of threats scribbled on bathroom walls and made in social-media posts.

A social media post wit several angry emojis stated, "I'm gonna shoot up the school."

The bathroom wall threats stated, "I'm shoot this b--ch up like Florida 12:15" and "You have 3 hours left till I shoot d-----."

Chief Johnson tweeted, "These threats must stop!"

Weatherford High School in Weatherford: Police took a 16-year-old student into custody Feb. 15 after the student made "vague" threats online that concerned other students. The unnamed student was transferred to a juvenile detention facility and charged with making a terroristic threat. Police did not find a firearm on the student.

Weatherford Deputy Chief Chris Crawford said: "With the national threat that's out there today ... it scares parents, and they have every right to be scared, and it scares students. It's a legitimate feeling of uneasiness when you have a fellow students that's posting something or writing something that others deem as threatening. No students or staff should have to live in fear."

Harmony Public School in Katy: Police arrested a 15-year-old student who was reportedly upset over the arrest of his friend for making threats. The teen posted a message on Snapchat that said: "You think you've seen a threat? I'll show you a threat." The teen's post was followed by a video of him shooting an AR-15 rifle and two pistols at a gun range.

The teen's friends reported the post to school administrators, and the suspect was arrested.

"This is not a game or a way to get attention," Fort Bend County Sheriff Troy Nehls said in a Facebook post. "I once against urge parents to have a conversation with their children regarding the seriousness of threatening posts." The student is currently at the county's juvenile detention facility.

That case came just a week after two other students were arrested for making threats on Snapchat against two area schools.

A 14-year-old student at Baines Middle School claimed he had plans to shoot up his school.

In another case, at Harmony Public School, a 15-year-old student posted a photo on Snapchat that showed students at the Florida school shooting running from the scene. The post indicated that the same thing would happen to seventh-graders and included a link with instruction on how to bring guns to schools undetected.

In both of those cases, students told their parents about the posts. The parents called school officials, who called police.

Vermont

Fair Haven High School in Fair Haven: Police arrested and charged Jack Sawyer, 18, with attempted aggravated murder, attempted first-degree murder and attempted aggravated assault with a deadly weapon. Vermont State Police said he had "communicated his desire to cause mass casualties" at the school.

Sawyer had intended to kill multiple students and the school resource officer with a 12-gauge shotgun.

A teen girl had alerted an adult about Sawyer's apparent plans to enter the school and cause mass carnage. She said his behavior "seemed strange" and that he had made previous threats against the high school.

Sawyer had been planning the attack for two years, and he outlined a detailed plan in his journal, which he titled "Diary of an Active Shooter." After he heard of the Feb. 14 Florida shooting massacre, Sawyer told his friend the killing spree was "fantastic" and that he supported it "100%."

"Only by the grace of God and the courage of the young woman who spoke up did we avert a horrific outcome," said Vermont Gov. Phil Scott.

Sawyer had been treated for Attention Deficit Hyperactivity Disorder and depression, according to his father. In his messages to the girl, he claimed he had stopped taking his medication.

Sawyer is being held at Marble Valley Regional Correctional Facility in Rutland. He pleaded not guilty in court Feb. 16.

Washington

Aces Alternative High School in Everett: As WND reported, one courageous grandmother in Washington, who saw alarming signs that her grandson was about to conduct his own high-school killing spree, acted quickly and likely saved many innocent lives. In Everett, Washington, police arrested Joshua Alexander O'Connor, 18, on Feb. 13 after he made "upcoming and credible threats" to murder students with a rifle and homemade explosive devices.

O'Connor's grandmother – who had read O'Connor's disturbing journal entries and learned of his plan – quickly contacted the Everett Police Department.

"I'm preparing myself for the school shooting," O'Connor reportedly wrote in one entry. "I can't wait. My aim has gotten much more accurate. … I can't wait to walk into that class and blow all those f---ers away."

He also expressed his desire to kill as many people as possible so his massacre would capture the public's attention.

O'Connor wrote: "I've been thinking a lot. I need to make this shooting bombing at Kamiak famous. I need to get the biggest fatality number I possibly can. I need to make this count. I've been reviewing many mass shootings/bombings (and attempted bombings). I'm learning from past shooters'/bombers' mistakes, so I don't make the same ones."

After reading the journal, the grandmother discovered a rifle stashed in the teen's guitar case. She then alerted authorities to her grandson's apparent plans.

"That would have probably been one of the hardest calls she has probably ever made," Everett Police Officer Aaron Snell told Seattle's KCPQ-13 News, "but I think the content of the journal and some of the other evidence in the house was enough that she was alarmed enough."

When detectives searcher the grandmother's home, they also found "military styled inert grenades and other evidentiary items." O'Connor had detailed his plans to make pressure-cooker bombs, activate inert grenades and use explosives to cause as much carnage as possible.

In the journal, O'Connor also wrote about an armed robbery of a local convenience store Monday evening. The teen admitted to police that he had participated in the robbery, and he claimed it made him feel powerful, according to KCPQ-13 News. He reportedly used the same rifle found in the guitar case during the robbery. Another suspect was reportedly involved in the robbery, and the two got away with $100.

O'Connor had planned to use the money acquired during the store robbery to fund his school massacre.

When police went to arrest O'Connor, the teen began running from authorities after slipping his hand out of the cuffs. O'Connor assaulted an officer, kicking him as he tried to flee.

On Wednesday, school officials praised O'Connor's grandmother for acting quickly to prevent the likely tragedy.

"The best defense against this kind of thing – the school shooting – is that if you hear something or see something, tell authorities. And that's exactly what she did," school district spokesman Andy Muntz told KCPQ-13 News.

O'Connor appeared in court Wednesday, and his attorney argued that he was only venting his frustrations in his journal.

"There is no ammunition. There is nothing else to suggest other than his statement in his journal," the attorney said.

The judge set O'Connor's bail at $5 million after the prosecutor argued that the teen is a threat to the community.

Wisconsin

Hartford Union High school in Hartford: Police arrested a 14-year-old student on Feb. 20 after another teen reported overhearing a conversation between two students in the hallway.

The arrested student reportedly said. "I'm going to shoot up the school."

Authorities say the student admitted to making the statement. Hartford police said the student "claimed they made the comment because they were having a bad morning."

The student claims he "never intended to act on the comment." No weapons were found in his possession. The teen's mother voluntarily turned over three firearms from their home.

The student may face charges of disorderly conduct.