Hamilton police say a 14-year-old girl was arrested Thursday after she was allegedly seen with a knife outside Sir Winston Churchill Secondary School.

The teen was arrested for uttering threats and carrying a concealed weapon, according to Jackie Penman, a police spokesperson.

In a letter to parents and students, acting principal Kristen Armstrong, said the girl was not a student at the school.

The letter states a "youth" was reported with a knife near the school and that police were "immediately" contacted.

"Students and staff deserve to be safe in school," wrote Armstrong. "If your child requires support as a result of this incident, please contact me or speak with your child's teacher."

Officials have also not provided any information about the alleged victim, but Miranda Finlayson says her son Mikey Mcentee was the student who was threatened.

Mcentee was a close friend of Devan Selvey, the 14-year-old who was fatally stabbed in the back behind Sir Winston Churchill on Oct. 7 and died in his mother's arms.

Two brothers, a 14-year-old and 18-year-old are charged with first-degree murder. Police allege the 14-year-old is the person who killed Devan.

'It's scary,' says mom

Finlayson says her son, who is also 14, told her he was talking with a friend in front of the school Thursday when some girls he had never seen before came up to him, flashed a knife and said something along the lines of "Would you like me to use it?"

Miranda Finlayson, seen here with her partner Alex Leeman, says a knife was pulled on her son Mikey Mcentee outside Sir Winston Churchill Secondary school Thursday afternoon. (Dan Taekema/CBC) "He told me he was threatened and he was scared," said Finlayson, adding it happened shortly after she had dropped him off after an appointment.

Mikey and his friend ran into the school and told a teacher who alerted police and his family, said Finlayson, who took her son out of school for the day.

"I'm freaking out," she said. "I don't know if I want him to go back."

She has other family members at Sir Winston and said she's worried about their safety.

"It's scary," Finlayson explained, adding she's not sure what led up the the knife being pulled, including whether it's connected in any way with him speaking out after his friend's death.

"We don't know if it has anything to do with Mikey's publicity … being all over the news. We don't know if it's retaliation, we don't know if it was just some girl coming up to him."