The shooting of a 28-year-old black woman in her own home by a white police officer in Fort Worth, Texas, has sparked protests over the Fort Worth Police Department’s treatment of city’s residents of color—and raised questions about whether local police can be trusted to investigate their own.

On Monday, Fort Worth Police Chief Ed Kraus identified Aaron Dean as the officer who shot Atatiana Jefferson, 28, at her home early on Oct. 12 and announced that Dean had resigned from the department. Dean was arrested at 6 p.m. on Monday at his attorney’s office, Kraus announced Tuesday.

“I ask you, please do not let the actions of one officer reflect on the other 1,700,” Kraus said Tuesday. “There’s absolutely no excuse for this incident and the person responsible will be held accountable. Miss Jefferson’s family and our community will have the last word. The courts will speak on her behalf.:

The Fort Worth Police Department said authorities are investigating the shooting, but Jefferson’s family has called for an outside investigation—and for Dean to be prosecuted.

Dean was arrested and booked in jail for murder charges on Monday, according to the Associated Press. The attorney for the family, S. Lee Merritt, tweeted that the family is relieved about the arrest but said the city has a lot of work to do moving forward”

Here’s what to know about the Fort Worth shooting, and how a call to a non-emergency number led to the death of a 28-year-old woman.

What happened?

At 2:23 a.m. on Oct. 12, Fort Worth resident James Smith called a non-emergency number, 311, to ask for a wellness check at his neighbors’ home. Smith told the operator that the neighbors’ front doors were open and all their lights were on, which was unusual for that time of night. He added that both the neighbors’ cars were in the house’s driveway, according to audio of the call.

Two police officers, including Dean, arrived two minutes later at the home, where Jefferson lived, police said. Body camera footage from the scene shows that Dean passed by the open door without knocking or calling out to the owners, and walked around the side of the house with a flashlight. Dean paused at a rear window, then shouted “Put your hands up! Show me your hands!” He then almost immediately fired a shot through the window, striking Jefferson. Police attempted to provide Jefferson with CPR, but she died on the scene, police said.

Jefferson was watching her 8-year-old nephew, who police said was in the bedroom with Jefferson at the time of the shooting.

Police released an image of a gun inside the bedroom. Kraus, the Fort Worth police chief, said the gun was “just inside the window” but declined to comment on whether Jefferson was holding the gun.

Who was Atatiana Koquice Jefferson?

Jefferson, 28, had moved into the house to care for her mother, Yolanda Carr, who was recovering from injuries from an unrelated incident, Jefferson’s family said at a press conference on Monday.

Amber Carr, her sister, said that Jefferson had been very close to Carr’s 8-year-old son, Zion, who was with Jefferson during the shooting. Jefferson had helped Zion get ready for school and worked to teach him to become more independent, she said.

Jefferson was playing video games with her nephew at the time of the shooting, Merritt wrote on Twitter.

Another sister, Ashley Carr, described Jefferson as a “smart, ambitious, kind person with a nurturing spirit.”

“Any neighborhood would be proud to have her as a neighbor… and yet she was killed by a reckless act,” Ashley Carr said.

Jefferson received a degree in biology from Xavier University of Louisiana in 2014, university President Reynold Verret said in a statement.

Who is Aaron Dean?

Kraus on Monday identified the white police officer who shot Jefferson as Aaron Dean. Kraus said that he did not know Dean’s age, but said that he was hired by the department on Aug. 21, 2017 and was commissioned as a licensed police officer on April 13, 2018.

Kraus said that Dean was placed on administrative leave on Sunday and later resigned from the police department.

“My intent was to meet with him today to terminate his employment with the Fort Worth Police Department. However the officer tendered his resignation this morning before we met,” Kraus said, and adding that that the department would continue the investigation as if he was still a member of the police force. He said that the officer’s records would note that he was “dishonorably discharged.”

Kraus also said that the officer has not been cooperative with the investigation, and has not yet taken any questions.

Dean has not yet hired an attorney, but the largest police union in Texas, Combined Law Enforcement Associations of Texas (CLEAT), will help to provide financial support, Executive Director Charley Wilkison told the Associated Press.

How has Jefferson’s family responded?

Bouquets of flowers and stuffed animals are piling up outside the Fort Worth home Monday, Oct. 14, 2019, where a 28-year-old black woman was shot to death by a white police officer. Members of the community have brought tributes to the home where Atatiana Jefferson was killed early Saturday by an officer who was responding to a neighbor's report of an open door. Jake Bleiberg—AP

Jefferson’s family is calling for Dean to be prosecuted for the shooting—and for outside investigators look into the shooting.

“There is simply no justification for his actions,” said Jefferson’s sister, Ashley Carr, calling for a “independent, thorough and transparent process.”

The family’s lawyer, S. Lee Merritt, has blamed the way the police responded to the 311 call for Jefferson’s death.

“They began creeping around and created a dangerous situation,” Merritt said.

How has the Fort Worth Police Department responded?

Kraus apologized for the shooting on behalf of the Fort Worth Police Department on Monday and said he would “demand” a thorough investigation of the incident. Kraus said that the police have presented a preliminary case to the FBI “to review the officer’s actions for possible civil rights violations.”

“You, Atatiana’s family and friends have my condolences, my apologies, and my prayers,” Kraus said.

Kraus said that he reached out to the Texas Ranger Division and discussed the possibility of having an outside agency conduct the investigation, but said it would be “not ideal” to hand over the investigation some time after the investigation started.

On Tuesday, Kraus said that the officers believed they were responding to an “open structure” call, which would have been treated more seriously than a welfare check. However, Kraus said Monday it would only be appropriate to fire into a home would be if someone was “actively firing” at the officers, and if they were alone in the room.

Police officials have been criticized for releasing an image of the gun in Jefferson’s home without indicating whether Jefferson was holding it at the time. Critics have described this as an attempt to blame Jefferson for her own death, or to justify the police officer’s decision to shoot her.

Merritt, the family lawyer, has called the department’s decision to release a photo the gun “obscene.”

Kraus has declined to comment on whether Jefferson was holding the gun at the time of the shooting, but said Tuesday that it “Makes sense that she would have a gun if she felt that was being threatened by someone in the backyard.”

Kraus said Monday that he understood the reaction to the release of the image of the gun, and that that decision would also be reviewed.

“In hindsight, it was a bad thing to do,” Kraus said. “I think it was to show there was a weapon involved. However, we’re homeowners in the state of Texas. I can’t imagine most of us—if we had somebody outside our house that shouldn’t be, and we had access to a firearm, that we wouldn’t act very similarly to how she acted.”

Kraus also responded to concerns that people would be reluctant to call the police in the future.

“I tell them I get it,” Kraus said. “Nobody looked at the video and said there’s any doubt that this officer acted inappropriately. I get it. We’re trying to train our officers better, we’re trying to shore up our policies and we’re trying to ensure they act and react the way that citizens intend them to. They act and react with a servant’s heart, instead of a warrior’s heart.”

On Tuesday, Kraus said that the department is working to bring in a third party to assess the department’s policies, training and practices. He also expressed sadness that the actions of one officer had destroyed the entire department’s work to build a relationship with the community.

“I liken it to a bunch of ants building an ant hill, and then somebody comes with a hose and washes it away. They just have to start from scratch and build a hill,” Kraus said.

How has the community responded?

Many community members have pointed out the racial dynamics in the case. Dean is white, and Jefferson and her family are black. Some say that the case is part of a larger pattern where police view people of color as threats, and use excessive force when patrolling their communities.

Hundreds of community members and local leaders gathered in Fort Worth yesterday to call for justice for Jefferson’s death.

Fort Worth is considered to be a majority-minority city. According to the U.S. Census Bureau, nearly 35% of residents are Hispanic and nearly 20% are black, while about 40% are non-Hispanic white.

Deborah Peoples, the chair of the local Democratic Party, tells TIME that members of the community have had enough of police brutality and with the failure of the city’s leadership to enact change. Peoples says that the community of color as a whole has “PTSD” from the violence.

At least five other people have been fatally shot by police officers in Fort Worth in 2019, and one other person was injured, according to the Texas Attorney General’s office records. At least eight officer-involved shootings took place in Fort Worth in 2018, according to the records.

“The police come into our community as if they’re coming into a war zone,” says Peoples, noting that the city needs to do more to combat a “systematic culture of racism.”

Peoples says that both the black community and the immigrant community are afraid to call the police because they believe they could be unjustly apprehended or harmed by the police.

Contact us at letters@time.com.