Law enforcement officers block the entrance to Marjory Stoneman Douglas High School February 15, 2018 in Parkland, Florida.Wilfredo Lee / The Associated Press

A South Florida teenager has been arrested after investigators learned he threatened Marjory Stoneman Douglas High School, the site of a mass shooting that killed 17 people on Valentine’s Day in 2018.

A caller reported seeing the threat late Wednesday night, according to the Broward Sheriff’s Office. Officials said the 17-year-old high school student texted his classmates in a social media chat room just after 9 p.m. Wednesday. The threat came a day after a student allegedly killed four classmates in Michigan.

“I want to shoot at tmrw school (tomorrow). When I sneeze, it’s a signal to go to the bathroom OK. Hope you’re not all snitches, ”the text message said, according to a probable cause affidavit.

Investigators found the student at his home and he was arrested Thursday morning for writing a threat to carry out a mass shooting, sheriff officials said.

School principal Michelle Kefford informed parents of the threat Thursday morning via a robocall. Stoneman Douglas has been at the center of the national debate and activism against gun violence in schools since a former student killed 17 people and injured 17 others in 2018.

The teenager’s mother told WSVN he didn’t think so, that it was a joke to him. She said they had lived in another country where schools were safe at the time of the Parkland massacre. “He is a normal child from a normal family and a safe environment. He doesn’t realize that the world is not that safe, ”she said.

“In my country, schools are very safe. Our state of mind is very peaceful. He just wanted to show off among his friends, ”she said. “This is no excuse for his behavior. It’s just an explanation of his behavior. All threats should be investigated. I understand that.”

Tony Montalto, chairman of Stand With Parkland, the group that represents families whose loved ones died in the 2018 shooting, said the threat “further proves the need for a timely investigation and notification to parents regarding threats against schools “.

“In the wake of this week’s shooting in Michigan and this incident … I urge our elected leaders at all levels of government to pledge to focus on the safety of students and staff ”Said Montalto.

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