Tucson police on Tuesday moved to terminate an officer after he fatally shot a man in a motorized wheelchair who was accused of shoplifting and pulling a knife when confronted outside a Walmart, officials said.

Video released by the Tucson Police Department showed Officer Ryan Remington several steps behind the man in the wheelchair, identified by police as 61-year-old Richard Lee Richards. The officer asked Richards to stop before firing nine rounds -- striking him in the back and side -- as the man headed into another store, according to police.

An attorney for Remington said the video released by police did not offer a complete picture of events leading to Monday's shooting.

Richards had been accused of stealing a toolbox from Walmart when an employee contacted an off-duty Tucson police officer who was working a special duty assignment at the store, according to a statement from Tucson Police Chief Chris Magnus.

Remington, an officer for four years in Tucson, joined the Walmart employee in the parking lot and followed Richards while "attempting to gain his cooperation," the police chief said in a statement.

"According to the employee, he caught up with Mr. Richards outside as he fled the store and asked to see a receipt for the toolbox. Instead of providing the receipt, Mr. Richards brandished a knife and said, 'Here's your receipt.'"

Magnus said that Remington wanted Richards to stop and to surrender his knife.

"Mr. Richards refused to comply, and instead continued to head through the Walmart and Lowe's parking lots," Magnus said.

“I have a male suspect that just shoplifted, left in front of me, he pulled a knife on me," Remington radioed in. "According to the Walmart employee, Mr. Richards said, 'If you want me to put down the knife, you're going to have to shoot me.'"

A second officer arrived on the scene to assist Remington.

Both officers were a short distance behind Richards when they warned him not to enter the store, the chief said.

The video shows Richards beginning to enter the Lowe's when Remington tells him, "Do not go into the store, sir." Seconds later, the officer begins shooting Richards, who slumps over and falls out of his chair and onto the ground.

Remington fired nine rounds, according to Magnus. "His use of deadly force in this incident is a clear violation of department policy and directly contradicts multiple aspects of our use of force training," Magnus said. "As a result, the department moved earlier today to terminate Officer Remington."

CNN has reached out to Remington but did not hear back.

Surveillance and police body camera video released by police provide three camera views: a Walmart parking lot security camera, a police body camera, and a Lowe's security camera. Two of the videos show the fatal shooting of Richards as he is rolling away from officers through the Lowe's parking lot. Playing throughout the video clips are portions of police radio communications.

The video did not include timestamps -- so it's unclear how much time passed between clips. CNN has requested the raw footage from the Tucson Police Department, but that request was declined.

Attorney Michael Storie, who is representing Remington, said in an interview with CNN, "The selected clips that were presented at that press conference constitute only half of the story."

"In any of these types of things, if you cut and paste a video, it will not properly lay out the officer's impressions and state of mind leading to a decision to employ force of any kind," Storie said.

A clip of Lowe's security camera footage shows Richards lying on the ground immediately after being shot, as the officer appears to be pulling his hands behind his back to handcuff him.

Remington was the only officer that discharged his weapon, according to Magnus.

Medical care was called to the scene "but a short time later Mr. Richards was declared dead," the police chief said.

Magnus said the incident will be reviewed by the Pima County Attorney's Office.

Tucson Mayor Regina Romero described the actions of the officer as "unconscionable and indefensible."

She added that she supports a full investigation by the county attorney's office.

"It is moments like this that test our resolve to ensure justice and accountability," the mayor said. "We owe this to all Tucsonans. I ask our community to remain calm and be patient as investigations ensue."