LOS ANGELES -- Southern California police shot and killed a Black man Saturday as he ran away from them while allegedly holding a gun, video showed.

The family of 23-year-old Rob Adams, however, says he was likely holding his cellphone instead of a gun because he had been talking to his mother when police arrived. His family expects to file a legal claim, a precursor to a lawsuit, on Thursday.

"All I heard after that was gunshots. He never told me goodbye," his mother, Tamika Deavila King, said Wednesday at a news conference.

San Bernardino police say that officers were called to a parking lot around 8 p.m. Saturday after getting a tip that a Black man was walking around with a gun.

Two officers, who were wearing uniforms but driving an unmarked car, saw Adams pull a gun out of his waistband and begin walking toward the cruiser with the firearm in his hand, according to San Bernardino Police Chief Darren Goodman.

The police department posted a nearly six-minute video to social media Tuesday that includes Goodman's narration, surveillance video footage and body-camera footage.

Though there is no audio of the initial encounter, Goodman said the officers gave Adams verbal commands.

The video shows Adams almost immediately turn around and run toward two cars that were parked up against a high wall.

"Seeing that he had no outlet, they believed he intended to use the vehicle as cover to shoot at them," Goodman says in the video.

Within seconds, one of the officers opened fire, striking Adams. He was pronounced dead at a hospital. Police recovered a 9 mm gun after the shooting.

The name of the officer who fired their gun has not been made public.

Ben Reynoso, a San Bernardino city councilman, blamed police for the shooting.

"Being that Adams never aimed the gun, was approached by an unmarked vehicle, and was shot while fleeing, therefore plausible criminality does not exist," Reynoso wrote Tuesday on Twitter. "In the end, Robert Adams is dead at the hands of the San Bernardino Police Department."

Civil rights attorney Ben Crump said Wednesday at the news conference that Adams' death was "a classic example of `shoot first and ask questions later." '

Crump and other attorneys representing Adams' family say police – who say he had "an extensive criminal history" – have made him out to be a villain.

"My son, Rob, wasn't a gang member. He was a good kid," his father, Robert Adams, said Wednesday. "What parent would want to see their kid killed on a video?"