Updated 8:06 a.m. ET
DENVER Two people who cleaners spotted breaking into a Denver middle school with what looked like rifles and backpacks late Monday night were taken into custody early Tuesday, police say.
The "rifles" turned out to be BB guns, authorities say.
Denver Police Chief Robert C. White says the suspects entered the Rachel B. Noel Middle School through a broken window.
A SWAT team was called to the scene and, after what White called a "cat and mouse game" that lasted three hours, the suspects were contacted, and surrendered.
White says the suspects are both juveniles but aren't thought to be students at the school.
He says they didn't have the rifles or backpacks when they gave up, but police later tweeted that they'd found the weapons and, "What appears to be assault rifles are more than likely BB guns."
No evacuations were ordered during the incident, but reverse 911 calls were made telling nearby residents to stay away from the scene.
Police said they hadn't heard of any threats against that or any other Denver school in recent days, and it would be open Tuesday, reports CBS Denver station KCNC.