Rumain Brisbon, an unarmed black father of four, was shot to death in Arizona Tuesday when a police officer apparently mistook his bottle of pills for a gun.

About 100 protestors marched to police headquarters in Phoenix Thursday, demanding the department release the name of the officer who shot Brisbon. A spokesperson reportedly defended the shooting, saying, "This one went bad from the standpoint of how it ended, but the officer was doing exactly what we want him to do."

Parts of the official police story have been challenged by some witnesses, the Arizona Republic reports.

According to police, a citizen reported a drug deal in a black SUV around 6 p.m. The officers went to investigate the car, where they saw Brisbon taking something out of the trunk. When they told him to put his hands up, cops say, he put his hands in his waistband, prompting one officer, a 30-year-old with seven years on the force, to pull out his gun. Then, the cops say, Brisbon tried to flee and the officer chased him down.

"During the struggle, Brisbon put his left hand in his pocket and the officer grabbed onto the suspect's hand, while repeatedly telling the suspect to keep his hand in his pocket," [police spokesperson Sgt. Trent Crump] said. "The officer believed he felt the handle of a gun while holding the suspect's hand in his pocket."

A woman inside an apartment opened a door at that moment, and the officer and Brisbon tumbled inside, Crump said. Two children, ages 9 and 2, were in a back bedroom, he said.

The officer could no longer keep a grip on Brisbon's hand and, because he feared that the suspect had a gun in his pocket, fired two shots, Crump said.

"It was so loud, I heard the vibration through the floor," Martin Rangel, who lives above the apartment where the shooting occurred, told the Arizona Republic. "I ran to the window, and that's when I saw the cop running out, or like, walking out, and he was cussing, you know, he was screaming, 'F—k, f—k,' like upset that he shot the guy."

Another witness, Brandon Dickerson, told the Arizona Republic he didn't see the officer try to talk to Brisbon before the confrontation began. An attorney for the family said "numerous witnesses" would refute parts of the official story.

Although police say they later recovered marijuana and a handgun from the SUV, the only thing Brisbon had on his person was a bottle of oxycodone pills.

He died on the scene.

[image via NBC]