SEATTLE - Seattle police officers shot and killed a 30-year-old mother of four at her apartment Sunday morning in front of "several children" when the woman "confronted" them with a knife, according to a statement from authorities. The Seattle Times said she had called police to report a possible burglary.At a vigil Sunday night, family identified the woman as Charleena Lyles, reported the Times, and said she had a history of mental health struggles. She was three months pregnant with her fifth child, they said, and too "tiny" for officers to have felt threatened by her - even if she had a knife."Why couldn't they have Tased her?" Lyles' sister, Monika Williams, told the Seattle Times. "They could have taken her down. I could have taken her down."Authorities offered few details Sunday of what led police to fire their weapons.Two patrol officers dispatched just before 10 a.m. Sunday to investigate a reported burglary at Brettler Family Place, an apartment complex for people transitioning out of homelessness, Detective Mark Jamieson said.Usually, only one officer would respond to a standard burglary call like this one, Jamieson told reporters. But police were familiar with Lyles and her apartment, he said, and her called flagged "hazard information" affiliated with her apartment that "presented an increased risk to officers," the detective said.Officers walked to the fourth floor and "at some point, the 30-year-old female was armed with a knife," Jamieson told reporters. Both officers, who have not been identified, fired their weapons. They performed CPR, according to authorities, but Lyles was later declared dead by fire department officials at the scene.The children inside at the time were unharmed. Police were trying to determine Sunday if the kids had witnessed the shooting.The department's Force Investigative Team is investigating the officers' decision to use deadly force. Both officers will be placed on administrative leave during the investigation, authorities said.Family members told the Seattle Times that they believe Lyles' race - she is black - was a factor in her death. Seattle police told the newspaper that the officers who shot her are white.Sean O'Donnell, captain of the department's north precinct, where the shooting took place, said one of the officers is an 11-year veteran of the force and the other is "newer to the department," reported the Times.King County jail records show that Lyles was arrested on June 5 on charges of harassment, obstruction of a public official and harassment of a law enforcement officer. She was released conditionally on June 14. Williams told the Seattle Times that one condition was that she receive mental health counselling, though the newspaper could not independently verify that information Sunday.Williams told TV station KOMO News that her sister's arrest earlier this month was connected to another incident at the apartment. Lyles was charged with obstruction because she refused to hand over one of the children to officers until her Williams arrived at the scene. She had scissors in her hand, Williams said."She didn't charge nobody or nothing," Williams told KOMO News.She said Lyles had "mental health issues" that were going untreated.Around a hundred people gathered Sunday for a vigil honouring Lyles. The mourners taped a photos of the woman and her children to the back of black plastic chairs and spelled her name out on the sidewalk with small votive candles. Friends and family wondered aloud how police could shoot and kill a mother in front of her children.Lhora Murray, 42, lives in the apartment directly below Lyles and told the Stranger she often heard yelling from the woman's unit and called security multiple times. When she heard gunshots Sunday morning, Murray said she called people - unaware it was officers who had fired their weapons.Murray told the Stranger that after the shooting, police handed her two of Lyles' children, a 10-year-old and a toddler. "They shot my mom," Murray said the 10-year-old told her as she took the kids outside.Seattle Mayor Ed Murray said in a statement that the shooting was "a tragedy for all involved.""My thoughts are with the many people impacted, including three children and the responding officers," Murray said.He promised a full and thorough investigation, citing "historic police reforms" that are "in place to address such crises."The Seattle Police Department has been operating under a federal consent decree since 2012, when a Department of Justice investigation found that officers used regular and widespread excessive force on the job, reported the Seattle Times.A court-ordered federal monitor issued a report in April asserting that the department had made a positive turnaround and that use of force by officers was down, reported the Times.The Washington Post