An unarmed black man was shot and killed by a white police officer in the US state of Oklahoma on Friday, with footage of the incident made public on Monday.

Multiple police video clips - from the ground and helicopter - show 40-year-old Terence Crutcher walking back to his disabled vehicle with his hands in the air, followed by multiple police officers. As he approaches the driver's door he appears to get shot first with a Taser and then a firearm.

Crutcher was fatally shot by officer Betty Shelby, but it's unclear what compelled her to draw her gun or what verbal exchange officers might have had with Crutcher. Local and federal officials have launched criminal investigations to determine whether Crutcher's civil rights were violated and what, if any, charges are warranted.

Video footage is also shot from a police helicopter overhead. Audio from that includes a man saying "time for a Taser." He then says: "That looks like a bad dude, too. Probably on something."

This narration is unfolding while Crutcher is walking back to his vehicle with his hands in the air, being followed and multiple police officers with weapons drawn. Moments later Crutcher collapses to the ground, apparently having been shot with a stun gun, before an officer radioes in to say "shots fired."

Call for criminal charges

Crutcher's twin sister, Tiffany Crutcher, is calling for criminal charges to be filed against the police.

"The big bad dude was my twin brother. That big bad dude was a father," she said. "That big bad dude was a son. That big bad dude was enrolled at Tulsa Community College, just wanting to make us proud."

In recent years there has been a series of deadly police shootings of unarmed black people, usually men, across the United States.

The deadly shooting comes just four months after former Tulsa County volunteer deputy Robert Bates was sentenced to four years in prison on a second-degree manslaughter conviction for shooting of an unarmed black man in 2015.

Shelby joined the Tulsa Police Department in December 2011. Before that she spent four years working as a Tulsa County sheriff's deputy. She has been placed on paid leave.

Tulsa Police Chief Chuck Jordan said the case was being investigated by local and federal prosecutors, he insisted that justice would prevail.

"I will make this promise to you: We will achieve justice in this case," 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."

bik/msh (AP, Reuters)