A SWAT team spent more than four hours in a standoff outside a Boulder apartment Friday night, before arresting a woman they say vandalized and stole from another apartment, then threatened officers with a knife and hammer.

The arrest of the suspect — identified as Helen Hartman, 26 — was made late Friday outside a third-floor apartment in a complex at 676 22nd Street. She was arrested on suspicion of second-degree burglary and second-degree criminal tampering.

Starting at about 6:40 p.m. Friday, police were camped outside the complex, and 22nd Street was closed between Baseline Road and Mariposa Avenue as SWAT negotiators worked to de-escalate the situation.

Earlier on Friday, Deputy Chief Curtis Johnson said, patrol officers responded to Hartman’s apartment on a report that she had broken into another unit, vacant at the time, to “remove some items and do some damage,” including spray-painting on the walls.

Johnson said that when police knocked on her door to speak with her about the alleged burglary, she appeared with a knife and hammer. Hartman then barricaded herself inside the apartment, which she was subletting from another woman.

While the suspect yelled at officers and threw items — including a bedroom door — at them from the third floor, the SWAT team exercised particular caution, Johnson said, because there was some question as to whether she was holed up with two children inside the apartment.

As detectives worked to secure an arrest warrant, police determined that Hartman was subleasing, and did not, in fact, have two kids with her.

“Ultimately,” Johnson said, “we put a robot outside one of the windows and tried to get her attention with the robot. Eventually, she stepped out the front door and turned towards the robot, at which time officers were able to grab her from the back and take her into custody just outside the front door on the landing.”

Police were uncertain of Hartman’s mental stability, “based on some of the behavior that’s been observed by the officers out there,” Johnson said.

With 22nd Street closed, residents and members of the public were not being allowed in the area.

Alex Burness: 303-473-1389, burnessa@dailycamera.com or twitter.com/alex_burness