CHICAGO (CBS) — The family of a man who was shot and killed by an off-duty Robbins police officer was speaking out for the first time on Tuesday, saying Chicago police have not been transparent about the shooting in West Pullman.

Joshua Jones, 20, was shot and killed on Friday near 124th and Wallace. Chicago police have said an off-duty police officer from Robbins shot Jones after an attempted armed robbery.

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The Robbins officer told Chicago police Jones had taken his car keys at gunpoint, and he shot Jones as Jones was getting into the car.

Police have said Jones’ weapon was recovered at the scene.

An autopsy determined Jones died of a gunshot wound to the back.

Jones’ family said they want justice. They said they don’t believe the police account, saying it doesn’t add up. They said Jones was shot four times in the back.

“The report said he started for his keys, he got in the car, and that’s when he opened fire,” said his mother, Angela. “If he was shot in the car, did he steal your keys? Did he steal your wallet? What happened?”

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Jones’ father, Marcus Rieves, said the family has been left in the dark about exactly what happened, and they need answers.

“I want justice. I need justice,” he said.

The Jones family said they fear a cover-up.

His family said Jones graduated from nursing school, but was preparing for a culinary career.

The Robbins officer involved in the shooting was not arrested, and has not been charged with a crime. Robbins police have said the officer has been placed on administrative duty.

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Area South detectives were investigating the shooting.