A Seattle family is demanding answers as to why officers on Sunday morning shot and killed a 30-year-old pregnant mother while her children were in the apartment after she called authorities to report a burglary.

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Police said Charleena Lyles confronted two officers with a knife before police opened fire, striking her in the chest and abdomen. She had called police to report a burglary at a home near Magnuson Park, on 62nd Street.

Lyles’ sister, Monika Williams, said she suffered from mental health issues, but insisted she was not a threat.

Police said they sent two officers to respond to Lyles’ burglary report because they her and were concerned for the officers' safety. The officers arrived at Brettler Family Place 3, an affordable housing complex, and went to the fourth floor, where they said Lyles confronted them with a knife.

"Both officers had to fire their service weapons, striking the individual," Detective Mark Jamieson said. Medics performed CPR on the woman for 10 minutes.

"Unfortunately, it is a fatality," Jamieson said. No officers were injured.

Police said several children were in Lyles' apartment when the she was shot.

"There's no reason for her to be shot in front of her babies," Williams said.

Lyles had an extensive criminal record. She was arrested June 5 on suspicion of harassment and obstructing a police officer and was released from the King County Jail on June 14. Her family said she didn't belong there.

"She has mental health issues that nobody's trying to (expletive) address," Williams insisted.

While she was in jail, Lyles learned she was three months pregnant, her family said.

The officers who shot her are on paid leave, following standard police procedure. Mayor Ed Murray promised a full investigation.

Lyles was featured in the Federal Way Mirror in 2008 after getting a job through a program for at-risk youth. Lyles was getting welfare when she entered the THRIVE program. She was placed in a position with the Poverty Bay Coffee Company in Federal Way, where she was permanently employed and no longer received welfare.

The Cox Media Group National Content Desk contributed to this report.