SAUGUS (CBS) — Police arrested a 16-year-old after they say he broke into a Saugus mall and stole a gun from a sporting goods store.

The incident shut down the Square One Mall for several hours Monday morning, as police searched the mall for what they believed was an “armed and dangerous intruder.”

The mall has since been reopened.

State and local police were called to the mall around 4:30 a.m. for a report of a break-in and broken window at the Dick’s Sporting Goods there.

Police said officers encountered the teen in the store, and said he was holding a long gun and ammunition he had taken from a display case. They then backed off and called SWAT officers in.

Police searched the entire mall and couldn’t find the teen, as he had escaped the building. Area schools briefly sheltered in place out of an abundance of caution.

“Originally, we thought he was in the building,” said Saugus Police Chief Dominic DiMella. “We had no reason to believe he got out of Dick’s Sporting Goods store.”

In a press conference shortly before noon, police said they had arrested the teen in Everett. Police are still searching for the weapon he was seen with.

They said they had contact with the suspect at the scene, but weren’t able to positively identify him until they viewed surveillance video from inside the mall.

Heavily-armed police officers were seen patrolling the area during the search for the suspect.

Scene outside Square One Mall right now in Saugus @cbsboston pic.twitter.com/Zod5iR3ydB — Nick Giovanni (@NickGNews) June 19, 2017

Chief DiMella said police conducted two sweeps of the mall out of an abundance of caution, and that area schools briefly sheltered in place.

“When you have firearms involved it rises to another level which necessitated the large scale of measured response of our mutual aid partners,” he explained.

The mall was reopened shortly after noon, but Dick’s Sporting Goods remained closed, as it is being treated as a crime scene.

WBZ NewsRadio 103o’s Doug Cope reports