Officers with the Seattle Police Department were no strangers to Unit 4303 in the Brettler Family Place apartment complex in the northeast part of the city. After they responded to at least three domestic violence calls there in the past year, the police were dispatched there again on Sunday morning to investigate a theft in Charleena Lyles’s unit.

Ms. Lyles greeted them at her front door, let them inside and then calmly explained that an Xbox video game console was stolen and a bag of clothes on her bed looked to have been disturbed, according to an audio recording of the officers. But after an officer repeated out loud what was stolen, the encounter suddenly escalated after the two officers present said they saw Ms. Lyles, 30, clutching a knife, the police said.

“Get back, get back, get back!” an officer yelled.

“Get ready,” Ms. Lyles responded, using an expletive.

“Tase her,” the other officer instructed his partner, but neither officer had a Taser.

Seconds later, the officers fired at least five shots, killing Ms. Lyles, as three of her four children were in the apartment. The family said she was pregnant.

The fatal shooting has outraged Ms. Lyles’s family, who said she struggled with mental illness after years of abusive relationships and threats of her children being taken away. It has also evoked similarities to past cases of Seattle officers using deadly force in encounters with people with mental health issues. Those episodes resulted in a Justice Department investigation, and the Police Department was placed under a federal consent decree in 2012.

“I don’t know if my sister had a knife or not, and even if she did, she was so tiny,” her sister, Monika Williams, said in a phone interview on Monday night. “There was no reason two trained police officers had to shoot her down.”

Her father, Charles Lyles, who lives outside Los Angeles in Lancaster, Calif., said he had spent Monday replaying the four-minute audio recording of the episode. He said he struggled to understand why the officers did not use anything but a gun, adding that she weighed about 90 pounds and had no history of violence.

“They were talking calm, and all of a sudden, you heard the gunshots,” Mr. Lyles said in an interview. “That really messes me up to hear her die.”

Officer Involved Shooting Investigation June 18, 2017
Video by SPD Blotter

The Police Department placed the two officers, whose names have not been made public, on paid administrative leave while the episode is under investigation — standard procedure in fatal shootings by the police. As required by Seattle police policy, both officers were equipped on Sunday with “less-lethal force options,” the police said, but they did not have Tasers. It is unclear if the two officers used any other nonlethal options.

Chief Kathleen O’Toole of the Police Department called the shooting a “horrible tragedy.” “The community is distraught,” Chief O’Toole said on Monday, according to The Seattle Times. “The family is distraught. The officers are distraught.”

When Ms. Lyles called the police on Sunday to report a burglary, the Seattle police said they intentionally sent two officers to respond to her apartment because of a confrontation on June 5. On that day, Ms. Lyles asked for help after a former boyfriend, and the father of her two oldest children, showed up unannounced at her apartment.

By the time the officers arrived around 11:25 a.m. on June 5, the man was gone, and the police found Ms. Lyles sitting on a couch holding large scissors next to her youngest child, a 1-year-old girl. Their guns drawn, the officers ordered her to drop the scissors, the police said.

Ms. Lyles refused. Still holding the scissors, the police said, she got off the couch and warned the officers, “Ain’t none of y’all leaving here today!” She then started talking about how the police were the devil and how she could morph into a wolf and clone her daughter, according to the officers’ description of the episode.

She eventually surrendered and was booked into the King County Jail on harassment charges. Unable to pay the $7,500 bail set in the case, Ms. Williams said, she spent 12 days in jail until a judge ordered her released last Wednesday on the condition that she seek mental health treatment.

Ms. Williams said her sister’s mental health was fine until about a year ago, when her four children were reported to child protective services for neglect. For the past year, Ms. Lyles had been fighting to prove to a judge that her children were in good care, her sister said, and that they were only at risk because of an abusive ex-boyfriend who is the father of her two youngest children.

In May 2016, the ex-boyfriend confronted her at her apartment and hit her, according to police records. Two weeks later, as she was trying to escape him, he bashed in her car windows as she was trying to drive away, according to the police and the family. The shattered windows sent glass falling on her children, which led child protective services to open a case because of concerns about their safety.

After those episodes, Ms. Lyles received a protection order against the former boyfriend, according to the police. But the man returned to her apartment in August and assaulted her again. He pleaded guilty to assault and was released from jail in February, according to court records.

“She had her teeth knocked out, had numerous black eyes. She has permanent scars from being abused, and she begged and begged for help,” Ms. Williams said about her sister. “Then she finally got the help, and then you take her life in front of her children.”