About 150 people marched peacefully to Phoenix police headquarters Thursday night to memorialize and protest the fatal shooting of 34-year-old Rumain Brisbon earlier this week by a police officer.

The protesters focused on similarities to cases that have sparked outrage and activism nationwide: Like Michael Brown in Ferguson, Mo., and Eric Garner in New York, Mr. Brisbon was black and unarmed, and the officer responsible for his death was white.

To the police – and to Brisbon’s mother – the case was not racially motivated. But the picture police paint of him is starkly different from the one his family and attorney put forward. Some witnesses have emerged with testimony contradictory to the police version of what happened during the Tuesday evening incident that left him dead.

In one version, Brisbon was a suspected drug dealer who fled and then got into a struggle with the officer, who thought Brisbon had his hand on a gun in his pocket. In the other version, he was a loving father innocently delivering fast food to his children.

Such different perceptions play into so much of the contact that minorities have with police that the demand for change has reached a sort of critical mass and will likely endure, says Tracie Keesee, a veteran police officer and co-founder of the Center for Policing Equity at the University of California in Los Angeles, which helps police apply social science research to improving their work.

“Nationally, there is exhaustion with this type of event,” Ms. Keesee says. “The community is saying, ‘We get your job is dangerous … but are you doing everything in your authority to make sure you don’t exacerbate the situation?.... When engaging communities of color are you doing it objectively?”

It will likely take months for the Phoenix police to complete their investigation into whether the shooting was justified, and that will be submitted to the Maricopa County Attorney’s Office for review, says Jerry Cobb, Attorney’s Office spokesman.

“We would like to see an independent agency investigate his murder instead of the organization that perpetrated it … and we’re waiting patiently for them to disclose the name of the officer who killed him,” says Marci Kratter, a Phoenix attorney working with Mr. Brisbon’s family.

The officer is a 30-year-old male who has been on the police force for seven years. He is currently on administrative leave.

Brisbon’s family members want him to be remembered as “a loving father and son” rather than just “another black man killed by police,” Ms. Kratter says. “It’s not about race; it’s about the individual.”

The police have “chosen to vilify the victim” by talking about his past criminal history, Kratter says. The Arizona Republic reports that he was convicted of burglary in 1998 and had a marijuana conviction and several cases of suspected driving under the influence.

According to the police account: The officer was investigating a report of drugs being sold from an SUV, and he drove to the apartment complex where the owner of the license plate was registered. He called for backup and then observed the driver get out of the SUV and remove something from the back seat. The officer commanded him to put his hands up, and when Brisbon put one or both hands in his waistband, the officer drew his weapon.

Brisbon fled, and when the officer caught up to him, Brisbon’s hand was in his pocket and the officer ordered him to keep his hand there. When a woman opened the apartment door, they fell into the apartment. The officer lost his grip on Brisbon’s hand, and “fearing Brisbon had a gun in his pocket the officer fired two rounds striking Brisbon in the torso,” the police statement says.

The item in Brisbon’s pocket was later determined to be a vial containing some oxycodone tablets, and a semi-automatic handgun was found on the driver’s side floor of the SUV, the police account says.

But Kratter and various media reports say some witnesses in the vicinity didn’t hear an officer shouting any commands before the shooting. Kratter also says it’s not yet clear whether the police have linked the gun to her client, since there was another person in the car.

“Even if he did have a gun in the car,” she says, “does that really justify murdering somebody?”

Police spokesman Sgt. Trent Crump confirms in an e-mail to the Monitor that there was an additional person in the car who “has been released at this point.”

Brandon Dickerson told the Arizona Republic that he was in the car with Brisbon and that Brisbon was dropping off fast food to his children. He did not see the officer try to talk with Brisbon and says his friend did not yell at the police, as the police account says.

“Who’s gonna argue with police?” Dickerson told the Republic. “He had no death wish yesterday.”

The Rev. Jarrett Maupin helped organize the demonstration Thursday.

“The Phoenix police department does not treat white people this way,” he said when pressed by interviewer Mark Curtis on 12 News/AZCentral.com about why this case has anything to do with race. Brisbon was simply delivering food to his children and was known by people at the apartment complex and was not a threat, Reverend Maupin said. “It’s wrong when we force people … to submit to aggressive and illegitimate stops and assaults by police.”

An assistant to Phoenix police chief Daniel Garcia attended Thursday’s rally and spoke with community leaders this week to help ensure that protesters could peacefully exercise their First Amendment Rights, AZCentral.com reports.

After an officer shoots someone, it’s easy to see afterward if that person was unarmed, but police officers sometimes have to decide if there’s a threat to themselves or the community “in the blink of an eye,” Keesee of the Center for Policing Equity says.

With that said, she adds, police departments do need to look at how they are training officers, and increasingly they are starting to focus on how to deescalate situations and consider the context of police tactics that may unnecessarily lead to encounters that are unsafe for police or suspects.

“Cops just don’t like change because we absolutely rely on what we know: ‘I’ve used this technique in the past and it’s worked for me.’ We have to learn to be a little bit more flexible, but when we talk about making changes … we want rational minds prevailing over how the training is done,” and that has to be a joint effort between communities and law enforcement, Keesee says.