Police in Wisconsin arrested a 13-year-old boy armed with a rifle in a bag after he tried to enter an elementary school but ran away when he was approached by staff.

The teenager, who is a student at Mahone Middle School in Kenosha, about 40 miles south of Milwaukee, arrived at Roosevelt Elementary School on Thursday morning with what police initially described as "suspicious bags." Officers arrested him, police said in a news conference.

Kenosha Police Chief Patrick Patton said the department received a video of the student wielding what appeared to be a firearm earlier in the day.

"We recognize this incident could've resulted in tragedy," Patton said. "Through the collaborative efforts of the Kenosha Unified (School District) and several law enforcement agencies, we're happy to report this incident ended peacefully."

Superintendent: School staff was 'heroic'

School officials said the student reached only the school's "secure entryway" and did not enter the school. The suspect fled into the neighborhood after school officials approached him and began to question him, said Kenosha Superintendent Jeffrey Weiss.

Weiss said the staff was "heroic" and credited the secure school entrance for the added protection. Weiss said the teenager tried to enter other doors that were locked before attempting to enter through the secure entrance.

That entrance had two doors, the first giving access to the office and a second to the school itself, Weiss said. The teenager entered the first door, but not beyond that. There, a school staff member approached the student, and at that point, he became "nervous and fled the building."

“They may not have known in the exact moment what was happening, but their actions were heroic and prevented the unfathomable,” Weiss said.

Police chief: Boy had searched about school shootings

Kenosha police said they arrested the boy on the 6700 block of 30th Avenue. Officials said no reason existed for the teenager to enter the school.

Patton said their investigation shows the suspect conducted internet searches on school shootings and made comments toward other students in recent weeks. In the video, it appears the teenager is practicing room-entry techniques, Patton said.

The police chief said these are things the department should have known before Thursday. He called on the community and parents to report "red flags."

“This is something that should’ve been known. This is something that had been told to people of his growing intentions. We know there are internet searches, and all the red flags we would look for and expect someone to report were there," Patton said. "We narrowly missed a tragedy today."

Schools were on secure hold Thursday

The student's attempt to enter the school prompted the Kenosha Unified School District to place all of its schools in a secure hold, which means the schools operated as usual, but no one could enter or leave the building. The district announced at about 2:40 p.m. that the hold was lifted, and school dismissal would be held as usual.

Patton said police also investigated a report of a shooter at Gateway Technical College, but it stemmed from a report from someone who received an initial police report on the elementary school incident and misinterpreted it.

Ruder said schools were placed in a secure hold based on guidance from the Kenosha Police Department.

The districtwide hold was for safety reasons as the suspect was sought by police, said Lt. Joshua Hecker, the department's public information officer. He said the department collaborated with the district, the Kenosha County Sheriff's Department and the Pleasant Prairie Police Department in the investigation.

"We understand the massive response and the fear in the community," the chief said on sharing the video and of the police response. "We want to make sure you understand what was driving that response."

In a statement release earlier in the day, the Kenosha school district said the sheriff's department and Pleasant Prairie police were at all county schools and assisting in patrols seeking the suspect.

Frank Elementary School posted on social media about the incident shortly after noon and said it was canceling afternoon 4K classes and holding any remaining 4K students.

"We understand this may raise concerns, but we assure you that this is being done for the safety of students, staff, and families. The school district is working closely with Kenosha Police Department to locate the suspect as quickly as possible," the school said in its post.

Jill Underly, the state superintendent of public instruction, released a statement Thursday night.

"I am so thankful for school staff in Kenosha for preventing a young person with a firearm from entering the building," she said. "Their quick actions protected students and ensured nobody was hurt. The threat of violence in our schools is real, and staff must prepare every day. Under the leadership of Superintendent Weiss, staff were well-trained – they saved lives today. I am so grateful for them."

Contributing: Drake Bentley

David Clarey can be reached at [email protected].

This story was updated to add new information.