A white, Atlanta-area police officer shot dead a naked, unarmed, and reportedly mentally ill African-American Air Force veteran at his apartment complex in Chamblee, Georgia on Monday, the third fatal police shooting of an unarmed black man in the last five days.

Witnesses said the victim, 27-year-old Anthony Hill, was acting erratically before the shooting—knocking on doors and swinging from a balcony—which led onlookers to call 911.

A maintenance man at the complex told the New York Times that Hill "was naked and on all fours in the parking lot when the police officer, who is white, arrived in his squad car, parking a good distance away."

The Times continued:

When Mr. Hill saw the officer, Mr. Castillo said, he stood up and moved toward him with his hands raised, and the officer, obviously frightened, yelled for him to stop. Mr. Castillo said that he had not seen a scuffle, but that he did see the officer pull out the handgun and shoot Mr. Hill.

The DeKalb County police officer has been identified as seven-year force veteran Robert Olsen. DeKalb County deputy chief operating officer for public safety, Cedric Alexander, told reporters on Monday that Olsen was armed with both a handgun and a Taser at the time of the shooting.

"What circumstance would have been more appropriate to use a Taser than this one in which you are 100 percent sure the man you are approaching is completely unarmed?" asked Daily Kos writer Shaun King. "It must have been obvious that Anthony was struggling through a psychotic episode of some sort. If this officer was trained to deal with those struggling with mental illness, as Dekalb County claims, what in his training did he use here? It appears nothing at all."

Hill—who played music under the name Ant Lanta, served in Iraq, and attended the University of South Carolina—had recently commented on the growing Black Lives Matter movement on social media.

The black community needs to work harder to make sure WE know that #blacklivesmatter. Our actions will either support or diminish our words.

— Lanta (@AntHeezie) March 6, 2015

Earlier this year, ACLU disability counsel Susan Mizner wrote about "people with psychiatric disabilities—most of them people of color—shot and killed by police."

"In many cases, police were responding to requests for assistance to get the person mental health care," she pointed out.

However, she added: "People with disabilities face violent and deadly consequences when law enforcement does not take disabilities into account. It is not okay to take a deaf person down for failing to follow verbal orders. It is not okay to attack someone with autism because he is slow to respond to instruction. It is not okay to treat a woman with a mental disability as if she were a dangerous criminal."

The Georgia Bureau of Investigation is examining Hill's shooting, and Olsen was placed on administrative leave pending the results of the probe.