Terence Crutcher shot by Tulsa officer Betty Shelby caught on cam

A videotaped police shooting of a black man in Tulsa on Friday has prompted the chief of police to ask the Justice Department to investigate and has the man's family crying foul.

Graphic video showing the shooting death of Terence Crutcher, 40, on Friday, went viral, adding the case to the list of police-involved shootings raising questions about relations between law enforcement in the United States and black men.

Police said they were responding to a call of a vehicle abandoned in the middle of the roadway. In video from officers' dashcams and also from a helicopter, four officers are seen responding as Crutcher holds his hands up in the air and walks away from officers, toward his stalled vehicle.

In the video taken from the helicopter, a male is heard to say, "That looks like a bad dude too. He might be on something."

Crutcher is then seen to fall to the ground.

Police said Crutcher did not respond to their comments and that one officer used a stun gun on him and another shot him.

Police Chief Chuck Jordan, meeting with reporters, assured that justice would be done and said he called in the Justice Department to ask for an investigation.

"I'm going to tell you right now that there was no gun on the suspect or in the suspect's vehicle," Jordan said. "I want to assure our community and I want to assure all of you and people across the nation who are going to be looking at this: we will achieve justice."

The chief added, "I would like to see us be a better city than some of the other cities we’ve seen. I hope some of my performance in the past has shown you we will do the right thing."

Crutcher's family and lawyer also held a press conference. They said they'd viewed the video and they saw no justification for Crutcher's shooting.

Crutcher's twin sister, Tiffany Crutcher, said the family demands to know what happened and wants charges pressed against police officer Betty Shelby, who shot and killed Crutcher.

"We ask for facts, we ask for answers, and we clearly got it through the video and we are devastated," she said. "The entire family is devastated."

Tiffany Crutcher, playing on the words of the male on the video shot from the helicopter, said her brother was a good man who loved God.

"That big bad dude was enrolled at Tulsa Community College," she said. "He just wanted to make us proud. That big bad dude loved God."