Updated

Tulsa police have asked the U.S. Department of Justice to help investigate the shooting death of a man by an officer.

Police Chief Chuck Jordan contacted the department through the U.S. Attorney's Office in Tulsa and will work with the agency to investigate Friday night's shooting death of 40-year-old Terence Crutcher, according to a news release from police.

Spokesmen for police and the Justice Department did not immediately return phone calls Sunday for additional comment.

Police spokeswoman Jeanne MacKenzie has said the shooting occurred after an officer stopped to investigate an SUV stopped in the middle of a street and Crutcher approached two officers who arrived to assist.

MacKenzie said Crutcher refused orders to put up his hands and was shot when he reached inside the SUV, which was his.

Police said one officer fired a stun gun, then the second officer fired his gun, striking Crutcher, who died later at a hospital.

Police have not said whether a weapon was found. Officials said that information, along with audio and video of the incident, will be released Monday.

Crutcher's twin sister, Tiffany Crutcher, told reporters Saturday that the family is heartbroken and she does not believe Crutcher was carrying a gun.

"We just want answers, we want to know what happened, there's a lot of speculation, but there is one thing, one fact that I do know is that my brother was unarmed."

She said her brother had left a class at Tulsa Community College when his SUV stalled in the street.

A phone number listed in the name of Crutcher's father has been disconnected.

The results of the investigation will be sent to Tulsa County District Attorney Steve Kunzweiler, who will determine whether the shooting was justified.

Kunzweiler did not return a phone call Sunday, but earlier told the Tulsa World that any police shooting is "a high-profile event," while he declined comment about the Crutcher case.