A teenager warns his friends that he's about to commit a shooting rampage at Otsego High School.

Milan Area Schools are evacuated after a bomb threat.

A 17-year-old is arrested and an AR-15 semi-automatic rifle is confiscated after the teen threatens to shoot up Brethren High School in Manistee County.

A dance at Carrollton Middle School near Saginaw ends with a lockdown, amid rumors that a student brought a gun to the event.

In the two weeks since a Feb. 14 school shooting in Florida killed 17 students and adults, dozens of Michigan schools have experienced threats or gone into lockdown mode amid security concerns.

That's also reflected in the huge spike in reports to Michigan's school-safety tip line, OK2SAY.

In the 12 days between the Parkland, Fla., shooting and Feb. 25, OK2SAY has received 94 calls, texts or emails about possible school attacks, according to Andrea Bitely, spokeswoman for Michigan Attorney General Bill Schuette.

The compares to four tips about potential school attacks received by OK2SAY during that 12-day stretch last year and 49 such tips for all of 2017, Bitely said.

"We're happy that more students are using OK2SAY," Bitely said. "At the same time, it's a bit concerning" to see the spike in reports.

"It's good that Michigan kids are coming forward when they see or hear something suspicious," Bitely said. "They know they need to tell someone, and they do."

There have no reports of actual school attacks, and the recent cases range from vague rumors to teenage pranks to empty threats by a disgruntled youth to something more serious.

In the Otsego situation, for instance, the student told several friends not to come to school on Feb. 22 because the student planned a shooting worse than the one in Florida.

The teen was arrested, but no weapons were found in the student's locker or possession, and authorities said it was unclear whether it was a credible threat.

"We take all these situations very seriously. We're going to follow through when kids make these (statements)," Otsego Superintendent Jeffrey Haase said last week.

The spike in threats is serious enough that Kent County Prosecutor Christopher Becker called a Feb. 23 press conference to warn people about the legal penalties of making a threat.

"It's fairly unprecedented to have this level of false reporting we are seeing based on something that happened in another part of the country," Becker said at the press conference, where he was accompanied by Grand Rapids Deputy Police Chief David Kiddle and Kent County Sheriff's Chief Deputy Chuck Dewitt.

Kent County authorities are investigating six recent threats, which were made at Caldedonia High School, Catholic Central High School, Grand Rapids Christian High School, KEC High School for special education students, Grand Rapids Aberdeen Elementary and an unnamed Grand Rapids Public school.

It's important for people to understand that making a false report or threat of terrorism is a 20-year felony, said First Lt. Michael Shaw, a spokesman for the Michigan State Police.

"This is a way to ruin your life," he said. "We don't consider any of these to be a joke. We will prosecute."

He said that youths or others "who think they can hide behind social media" in making a threat are "making a big mistake."

Shaw added that parents need to be monitoring their children's social media accounts.

"If your child has a social media account, and you don't know the password, you're doing something wrong," he said.

The good news, say authorities, is that in Otsego and other schools, students are coming forward when they hear something suspicious.

"We want that uptick in tips," Shaw said. "We'd rather go out a 1,000 times and find there's nothing to it."

Haase has said that school officials were alerted to that potential threat in Otsego by students who overheard the suspect talking about his plans.

"We want to commend these students for speaking up and alerting us to this situation," Haase said in an email to parents.

Bitely and Shaw credit the OK2SAY program for giving students an outlet to make anonymous tips about school safety. OK2SAY tips can be submitted online or via text, phone, email or using the OK2SAY app.

They said the tip line collects information about issues ranging from a student who keeps a gun in his or her school locker to reports of a possibly suicidal classmate to a disturbing social media post.

"By far, most of the tips are about bullying," Shaw said.

The tip line is monitored by the Michigan State Police, and information collected is passed onto school officials and local law enforcement, Bitely said.

She said the tip line has thwarted school attacks, including a recent case involving Columbia Central High School in Jackson County.

Wendy Zbed, executive director of the Michigan Association of Secondary School Principals, said she isn't qualified to say what's behind the recent spike, other "than to acknowledge there is an uptick."

Because there's such a range in the type and severity of threats, "there's no one thing that's going to address the problem," she added.

She said her organization and others that work with Michigan schools, such as the Michigan Association of School Administrators and the Michigan Association of School Boards, have been reaching out to their members and urging them to ensure they have policies and protocols in place to deal with such threats.

Like Bitely, Zbed also urges students and parents to work with schools on addressing the problem.

"At this time of heightened awareness and tension, people need to report anything that's suspicious," Zbed said. "Don't just think it's no big deal."