KENOSHA, Wis. (AP) — A 13-year-old boy who tried to enter a Wisconsin elementary school while armed was taken into custody after fleeing when confronted by school staff, authorities said.

Kenosha police said they believe the boy had a firearm when he was stopped around 9 a.m. Thursday while trying to enter Roosevelt Elementary School with a backpack and a duffle bag in the city about 35 miles (55 kilometers) south of Milwaukee.

School staff questioned the teen in the school’s secured entrance area, and surveillance video showed a large black bag at the youth’s side, police said.

“We believe that this was actually an armed suspect with a firearm and there was no legitimate reason to enter the school,” Kenosha Police Chief Patrick Patton said at a Thursday news conference, adding that “a tragedy was averted today.”

“The only reason the individual was not able to fully enter the school was because of the quick and diligent actions of the school staff,” Patton said. The boy immediately fled on foot when school staff approached him, he said.

Police have not released the boy’s identity or said how they had access to the gun. They said the suspect’s mother is cooperating with police, WISN-TV reported.

Police said the student who was in custody attends Mahone Middle School and was a former Roosevelt Elementary student. He was intercepted by police around 2:05 p.m. during a communitywide search.

Kenosha Unified School District Superintendent Jeff Weiss said that the “suspect actually tried numerous outside doors and entrances before coming around to where our secured entry is.”

Investigators “have information that the suspect performed multiple internet searches related to school shootings prior to the incident,” Patton said.

Patton said the suspect had shared videos and made several comments to fellow students for weeks leading up to Thursday.

“This is something that had been told to people of his growing intentions. We know that there is internet searches and all the red flags that we would look for and expect someone to report were there,” he said.

All Kenosha Unified schools were placed on a “secure hold” lockdown for the rest of Thursday.

There are no classes Friday at the school; the district had previously scheduled a day off for students for a staff workday.