ABC News(FORT WORTH, TX.) — The police officer who fatally shot a Fort Worth, Texas, woman in her home while answering a call for a welfare check abruptly resigned on Monday just before he was about to be fired for allegedly violating multiple department policies, the police chief said.

“I certainly have not been able to make sense of why she had to lose her life,” Fort Worth Police Chief Ed Kraus said at a news conference in reference to the early Saturday morning killing of Atatiana “Tay” Jefferson. “On behalf of the men and women of the Fort Worth Police Department, I’m so sorry for what occurred.”

Kraus identified the officer who shot Jefferson, 28, as Aaron Dean, who joined the police force in April 2018.

Kraus said he was scheduled to meet with Dean on Monday morning, but the officer tendered his resignation before they had a chance to meet.

 “Had the officer not resigned, I would have fired him for violations of several policies, including our use of force policy, our de-escalation policy, and unprofessional conduct,” Dean said.

He said an internal investigation and a criminal investigation of Dean would proceed, and that he has sent a preliminary report of the shooting to the FBI to launch a civil right’s investigation.

Kraus made the announcement just hours after loved ones of Jefferson demanded the officer be immediately fired and arrested, and that the federal government take charge of the investigation.

Jefferson’s family spoke out at a news conference to demand justice.

“This man murdered someone. He should be arrested,” said Jefferson’s brother, Adarius Carr, a member of the U.S. Navy.

“I’ve served my country for the last 12 years. In that time, I’ve been trained and taught that there are preplanned responses for everything you do. Everything you’re trained about, there’s a way to do things. And when you don’t do it the way you’ve been trained or the way you’ve been taught, you have to answer for that,” Carr said. “The Fort Worth PD cannot investigate themselves. The U.S. Navy is not allowed to do it, they should not be as well.”

Lee Merritt, a civil rights attorney representing Jefferson’s family, said the shooting shows that the Fort Worth Police Department is “in need of serious systematic reform.”

“Of course this family is calling for the firing of this officer. That’s benign. That’s the least that we should expect,” Merritt said.

Merritt said the family is calling on the Department of Justice or the FBI to investigate the killing, adding that the officer, whose name had not been released, should be “vigorously prosecuted.”

“We expect this to happen immediately,” Merritt said. “This (the shooting) happened Saturday. Why this man is not in handcuffs right now is a source of continued agitation for this family and for this community, and it must be addressed.”

UNACCEPTABLE! The acts of yet another “trained” police officer have resulted in the death of #AtatianaJefferson. Gun downed in her own home. If we are not safe to call the police, if we are not safe in our homes, where can we find peace? We demand answers. We demand justice. pic.twitter.com/UZqHQzPyaW

— NAACP (@NAACP) October 13, 2019

The shooting unfolded about 2:30 a.m. on Saturday after a neighbor of Jefferson’s called the police department’s non-emergency line to asked that a welfare check be conducted on Jefferson’s home because the lights were on and the back and front doors were open.

Lt. Brandon O’Neil said at a news conference Sunday afternoon that two officers were sent to the home on East Allen Avenue. He said the officers arrived at the house at 2:29 am. and parked near Jefferson’s home, but not in front of the residence.

O’Neil said the officers walked around the back of the house, and that one of the officers observed a person through the rear window of the home and opened fire.

Body-camera footage released by the department shows the officer approaching a rear window of the home with his gun drawn. The officer sees the woman through the window, shouts, “Put your hands up, show me your hands,” and fires one shot.

“Perceiving a threat, the officer drew his duty weapon and fired one shot striking the person inside the residence,” a statement from the police department reads.

Responding officers entered the home, located the shooting victim and began providing emergency care.

Jefferson died at the scene.

O’Neil said the officer who opened fire on Jefferson never identified himself as a police officer.

“What the officer observed and why he did not announce ‘police’ will be addressed as the investigation continues,” O’Neil said.

Merritt said that Jefferson and her 8-year-old nephew Zion were playing video games when they heard someone in the bushes outside their home and went to a bedroom window to investigate. He said Jefferson stopped her nephew from looking out the window, that she was shot when she peered into the darkness.

“It was less than a second,” Merritt said of the shooting. “I had an expert slow it (the body-camera video) down. It was .6 second between the command and the shot. There was no time for them to perceive a threat from a weapon. There was no time for her to respond. It was reckless, deadly behavior.”

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