Updated 07/29/13 – 10:57 a.m.

CHICAGO (CBS) — Police officers shot and killed a man who was stabbing his ex-girlfriend with a butcher knife, outside her home in the Gage Park neighborhood.

CBS 2’s Susanna Song reports the 27-year-old mother of three was stabbed in the left arm by her children’s father, only a few feet away from where Chicago police officers stood waiting on the front steps, thinking she was safe and out of harm’s way.

The woman called had police around 10 p.m. Sunday, to say her ex-boyfriend was following her in violation of an order of protection. The woman said she ran into him at a store near 51st Street and Kedzie Avenue, and he followed her to her home near 52nd and Mozart streets, carrying a large butcher’s knife.

Police officers met her outside, where she told them her ex-boyfriend was gone. The officers then asked her to go back inside and grab a copy of the order of protection.

After she went to the back door to go inside, police heard hear screaming, and ran into the gangway to find her ex-boyfriend on top of her, stabbing her with a foot-long butcher knife, according to Chicago Fraternal Order of Police spokesman Pat Camden.

“At that point, he saw the police coming at him, and stood up and charged the police with the knife, and at that point he was shot and killed,” Camden said.

He said officers did not realize the man was hiding nearby when they arrived at the scene.

“The offender actually drove away from the house, parked on the next block, and came through the alleyways and what not, laying in wait for the complainant to come into the house,” Camden said.

The victim’s brother said he was outside with police and they had all assumed the ex-boyfriend had fled the scene before officers arrived.

“He was hiding in the back door. … I think he probably jumped the fence in the back. So we didn’t know he was there, otherwise we wouldn’t have let her go,” Tomas Hernandez said. “It’s been a tough night, for all of us; but, likely, she’s okay, and fortunately he’s gone,” he said.

The woman’s children – ages 10, 9, and 5 – were inside the house at the time, but were not injured.

Authorities have not released the ex-husband’s name. He was pronounced dead at the scene. Camden said the man is a convicted felon.

Relatives said the woman and her ex separated in February, because he had become violent.

The woman was taken to Mount Sinai Hospital with several stab wounds, but was released from the hospital Monday morning, and was resting at home.

The Independent Police Review Authority was investigating.