Home surveillance video allowed a Butler woman to view in real time a trio of masked and armed men burglarizing her house Saturday night, police said.

The 28-year-old woman was at work when she watched images that showed the men, all carrying what appeared to be semi-automatic rifles, in her rental home in the 400 block of Brown Avenue.

No one was at the two-story house and no one was injured. The masked and glove-wearing gunmen reportedly made off with about $1,000 in currency.

Butler Deputy Police Chief David Adam believes the unknown suspects were expecting someone to be home when they showed up shortly after 9:10 p.m. They intended to rob whoever they found there.

“To me, and it’s speculation, this was a home invasion that no one was home for. I mean, who brings AR-15s to a burglary?”

Investigators suspect each man was toting what looked like an AR-15 rifle, the civilian version of the M-16 military rifle.

The woman, who lives with a female roommate, was at work when the surveillance system in the home notified her cell phone of the apparent break-in. The alert was touched off by the motion detector.

The notification instantaneously allowed her to see what was going on in real time.

The lone camera was set in the home’s living room, police said. It caught the three suspects inside.

Moments earlier, police said, one of the burglars used a pry bar device to force open a rear door.

“The dead bolt was bent, the door jamb broken and the door was pried open,” Adam said.

The suspects passed the camera and appeared to waste little time before they headed upstairs. They were on the second floor, out of video range, police said, for only a minute.

But during that time, the crooks were able to steal $1,000 that was in a guest bedroom. The victims told police that $750 of that money was intended for the month’s rental payment.

Immediately after getting the high-tech tip about the burglary, the victim at work called 911 to report the crime in progress.

“She said there were three males with masks and guns in her house,” Adam said.

She also called her roommate to make sure no one was home.

A neighbor reported seeing the trio running away from the back of the house, police said.

Police initially reported that they believed the suspects drove away in a car. They later backed away from that theory.

Adam said it was not known if a getaway car was used. He believes, however, that the suspects barely got away by the time officers arrived.

Police later viewed the recorded video for themselves. They also interviewed the occupants, who could not provide any clues about the suspects’ identities.

The women also apparently didn’t know why they were targeted.

“The (28-year-old) said she got into an altercation with a female several days earlier,” Adam said. But it was not known if that altercation played any role in the crime.

Police, meanwhile, said the guns looked like legitimate firearms.

“Who knows if they’re real or not,” he said, “but they damn sure looked real to me.”

Police released video and photographic evidence of the crime scene in hopes of generating tips from the public.

The images were also meant to warn the public.

“The suspects,” Adam said, “should be considered armed and dangerous.”

Anyone with information is asked to call police at 724-287-7744, or 911.