Alexis Wilson was working an afternoon shift at the local Pizza Inn in McAlester, Oklahoma, on Sunday, when she pulled a co-worker aside to boast about her new gun.

The slight 18-year-old with large brown eyes clutched her iPhone and pressed play on a video of her shooting a newly purchased AK-47, according to an incident report. Then Wilson told the other teenage waitress how much she resented the people at her old school - allegedly adding that she wanted to "shoot 400 people for fun."

The chilling conversation shook Wilson's co-worker. She reported it to a manager, who called the McAlester police.

On Monday, the Pittsburg County Sheriff's Office said Wilson was charged with a felony for making a terrorist threat against McAlester High School.

"In today's times, you can't say stuff like that," Pittsburg County Sheriff Chris Morris told KTUL. "We're going to take it serious and investigate it to the fullest extent and make an arrest if possible because we do not want any of our schools getting shot up - nobody does."

Wilson has pleaded not guilty. Her lawyer did not immediately return a request for comment.

The 5-foot-7, baby-faced teenager is an anomaly as a female suspect allegedly plotting a mass shooting, but police described her as a serious threat.

The high school she allegedly targeted had suspended her once for bringing a knife to school and again for displaying swastikas on her personal belongings, a school resource officer told the sheriff's office. Her booking photo shows Wilson wearing a T-shirt referencing "The Anarchist Cookbook," a 1971 book advocating for violent civil disobedience that has been found among the belongings of school shooters. On Facebook, Wilson had liked a documentary about the 1999 Columbine High School massacre.

Norway mosque shooting: Worshipper disarms gunman as he begun to fire Show all 16 1 /16 Norway mosque shooting: Worshipper disarms gunman as he begun to fire Norway mosque shooting: Worshipper disarms gunman as he begun to fire Philip Manshaus, charged with murder and attempted act of terror, appears in court for his detention hearing. The 21-year-old Norwegian man is also alleged to have killed his teenage stepsister before targeting the Al-Noor Islamic Centre in the Oslo suburb of Baerum. EPA Norway mosque shooting: Worshipper disarms gunman as he begun to fire The attacker, who was reportedly wearing a uniform and body armour, broke through a glass door to reach the place of worship, where people were preparing to celebrate the Islamic festival of Eid al-Adha. NTB scanpix/Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire Worshipper, Mohammad Rafiq (right), 65, tackled the gunman who stormed the mosque. Witnesses said Mr Rafiq restrained the terror suspect and held him down with another worshipper before police arrived, despite being injured in the struggle. Speaking to press outside a nearby hotel on Sunday, he said: “I’m thankful for all of the help and support I have received.” He told how he held the gunman down while another worshipper, Mohamed Iqbal, hit him on the head. Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire A Norwegian police expert manipulates a robot in front of the al-Noor islamic center mosque NTB scanpix/AFP/Getty Norway mosque shooting: Worshipper disarms gunman as he begun to fire Irfan Mushtaq, board member of the mosque, said that minutes before the shooting on Saturday afternoon around 15 people had been inside the building. NTB scanpix/Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire Following the attack on Saturday, police said Manshaus had hoped to kill with reports suggesting he had entered the building with at least two rifles and wearing body armour. Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire Manshaus' facial bruising is said to have been sustained in the desperate fight inside the mosque in which 65-year-old worshipper Mr Rafiq managed to disarm the assailant as he begun to fire his weapon. AP Norway mosque shooting: Worshipper disarms gunman as he begun to fire Manshaus – who smiled during the hearing – did not speak in court but his lawyer Unni Fries (right) told reporters later that “he will use his right not to explain himself for now”. EPA Norway mosque shooting: Worshipper disarms gunman as he begun to fire When officers later raided his nearby home, they found the body of his 17-year-old stepsister, who he is suspected of murdering beforehand. Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire Norwegian Prime Minister Erna Solberg, beside Mohammad Rafiq (left) told media that they are trying to combat hate speech with a special action plan targeting education, as well as, elderly people with more extreme views towards Islam. NTB scanpix/Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire People gathered outside the Islamic Cultural Centre in Oslo to show solidarity with the Muslim community after Saturday's shooting NTB Scanpix/Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire In other developments on Monday, the head of Norway’s domestic security agency said officials had received a “vague” tip off a year ago about the suspect, but that it had not been sufficient to act because they were given no “concrete plans” of an attack. EPA Norway mosque shooting: Worshipper disarms gunman as he begun to fire Hans Sverre Sjoevold, head of Norway’s PST agency, told a news conference that his organisation received many tips every day and that, in this case, the information “didn’t go in the direction of an imminent terror planning”. Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire Muslims from the Al-Noor mosque had to move prayer to a hotel on the first day of Eid al-Adha due to the shooting NTB scanpix/Reuters Norway mosque shooting: Worshipper disarms gunman as he begun to fire The suspect’s lawyer declined to comment on Norwegian media speculation that Manshaus was inspired by New Zealand mosque terrorist attack where a gunman killed 51 people in March. NTB scanpix/AP Norway mosque shooting: Worshipper disarms gunman as he begun to fire Reports suggest that the would-be terrorist wrote online that he had been “chosen” by the Christchurch gunman to carry out his own atrocity. Prosecutors have now asked for him to be held on terror charges for four weeks. NTB scanpix/AP

"A female can pull the trigger just as easily as a male," Morris told KTUL Monday. "It's rare, it's different. I don't know that there's been a female accused of this."

Female school shooters are far more rare than their male counterparts, but not unheard of. One of the most well-known was 16-year-old Brenda Spencer, who opened fire on an elementary school in 1979 through the window of her home, killing two adults and injuring eight children and one police officer. Spencer became infamous for the motive she offered a reporter who phoned her during the attack. "I don't like Mondays," she reportedly said. "This livens up the day."

After Wilson's shift at the pizza shop ended on Monday, Sergeant Micah Stites and Deputy Matthew Jordan knocked on Wilson's front door. Wilson agreed to talk, police said.

She denied showing her co-worker a video of her shooting the AK-47, but admitted she had talked about the gun and had showed off photos of her posing with it. She played videos of her shooting the rifle for Stites and Jordan, police said. During the interview, Wilson appeared nervous to the sheriff's officers. Her voice shook and she jumped from topic to topic mid-sentence, they said.

The young woman told Jordan she had "disturbing and criminal-like things" on the phone. She said she was bullied at McAlester High School.

After she had been suspended in her freshman year, she said, she completed a program at Thunderbird, a military academy in Oklahoma that advertises itself as an alternative option to public school. She said she tried to re-enroll at McAlester High afterward, but she hadn't been allowed to start classes this fall. Wilson explained the alleged threat by saying she had been trying to convince her co-worker that "not everyone that owns a gun is a bad person," the police report said.

"She said that she would never shoot up a school or people," Jordan wrote in his report, "and that her co-worker must have taken what she said wrong."

Stites and Jordan collected an iPhone with a purple case, an AK-47 with six magazines and a 12-gauge shotgun with a stock sleeve for extra shells from Wilson's bedroom.

At the end of the police interview, Wilson told the officers that she used to feel "suicidal and borderline homicidal" torward her classmates at McAlester High because of the bullying she faced. Jordan asked her if she thought about hurting anyone at the school.

"Not recently, but she has in the past," the report says.

Wilson's mother, Sonya Smith, said her daughter is innocent at Monday afternoon's arraignment hearing, the McAlester News-Capital reported. She told sheriff's deputies that she knew about her daughter's guns, but "didn't think anything of it" because Wilson had long been a marksman and hunter.

The school district's superintendent, Randy Hughes, said that McAlester High would be open on Tuesday.