Updated at 7:30 p.m. Monday: Revised to include comments from the Jean family's attorneys at a news conference.

Dallas police Officer Amber Guyger saw only a silhouette across the room in a dark apartment Thursday before she shot 26-year-old Botham Jean, according to an arrest warrant affidavit made public Monday.

Amber Guyger (Kaufman County Sheriff's Office)

Jean, who lived on the fourth floor of the South Side Flats in the Cedars, was home alone when Guyger mistook his apartment for hers, the affidavit says. Guyger lived on the third floor, directly beneath Jean's apartment, but mistakenly parked on the fourth floor after finishing her shift at the Dallas Police Department, the affidavit says.

When she arrived at the door, Guyger inserted her unique door key embedded with an electronic chip into the keyhole, investigators wrote. The door was slightly ajar, so the force of inserting the key pushed it open.

The affidavit states the apartments' "respective interior floorplans are in most ways identical or extremely similar."

Botham Jean (Jeff Montgomery / Harding University)

The apartment was dark and when she saw "a large silhouette," Guyger thought she was being burglarized, the affidavit says.

Guyger drew her gun, "gave verbal commands that were ignored" and fired twice, investigators wrote. Jean was struck once in the torso.

Guyger then called 911 from her cellphone and started giving first aid. She turned on the lights, then returned to the front door and realized the apartment wasn't hers, the affidavit says.

She told the 911 operator as well as responding officers that she had thought she was at her apartment when she shot Jean, according to the affidavit.

Jean was taken to Baylor University Medical Center, where he died.

Lawyers for Jean's family disputed the narrative in the arrest warrant affidavit at a news conference streamed live by WFAA-TV (Channel 8) Monday evening, saying Jean was a meticulous man who wouldn't have neglected to close and lock his door.

One attorney, Lee Merritt, said two independent witnesses had come forward to say they heard knocking on the door in the hallway before the shooting. Merritt said one witness reported hearing a woman's voice saying, "Let me in, let me in." Then they heard gunshots, he said.

After the gunshots, one of the witnesses reported hearing what she thought was a man's voice saying, "Oh my God, why did you do that," Merritt said.

He said he believes those were Jean's last words.

One witness said she didn't report what she had heard to law enforcement, Merritt said, but did reach out to Jean's family because she thought what she heard contradicted the prevailing theory.

"This affidavit is very self-serving," said lawyer Benjamin Crump, who is also representing the family. "Botham Jean is not here to give his version of what happened because he's dead."

The Texas Rangers got a search warrant for Jean's apartment because after interviewing Guyger, they believed that "a possibility exists that Subject Jean was expecting an unknown visitor" and that a cellphone or laptop may show evidence of that, according to an affidavit.

A return for the warrant shows the Rangers collected an iPhone from the living room. They didn't take Jean's laptop, which they noted was damaged.

Guyger was arrested on a charge of manslaughter Sunday night and was booked into the Kaufman County Jail. She posted bond and was released the same night.

Neither affidavit detailed the length of the shift Guyger had worked before the shooting, but a law enforcement official with direct knowledge of the case said the officer had just finished a 15-hour day before she parked on the wrong level of the parking garage.

It's not unusual for members of a special team to work long days, Dallas Police Association President Mike Mata said. On the day of the shooting, Guyger and other members of a team that targets high-crime areas had helped arrest multiple suspects linked to robberies, he said.

Police supervisors "try to make sure you have at least six hours' worth of rest before you come in," though that's not written policy, Mata said.

He noted that staffing gaps have made overtime work commonplace as the Police Department has shrunk by hundreds of officers in recent years.

Many Dallas officers also work part-time jobs to supplement their income, Mata said. Those off-duty jobs have to be approved by the department, and under local policy, the total workday can't exceed 16 hours.

However, the police chief or division commander can approve longer workdays.

The arrest warrant affidavit provided the first official account of what happened the night Jean died. Without it, misinformation swirled on the internet.

For instance, social media users ripped a photo from Jean's Instagram account and misidentified a woman pictured with him as Guyger, in an effort to prove that the two knew each other before the shooting. They apparently did not.

Mata said he is concerned about social media users passing along false narratives and rumors. Guyger has received threats online and through her phone.

"Someone got her cell and was sending her texts," Mata said. "And her address is on the arrest warrant."

He said "she is somewhere safe, away from that address."

Mayor Mike Rawlings said in an interview Monday that he was also trying to sort through the misinformation and strange details of the case.

Initially, the mayor said, he was told Guyger had been working an off-duty job — "and that was wrong."

More misinformation spread over the weekend, to the point that Rawlings is now all but pleading with people "to stay off social media."

But then his "mind starts to work like every other citizen's in town about how could that happen, what does that mean 'she got the wrong apartment,' what's the key situation, how do they get in? You become a detective right there," he said.

"And then you say, 'That's not my job.'"

Staff writers Julieta Chiquillo, Tom Steele and city columnist Robert Wilonsky contributed to this report.