Dashboard camera video released on Tuesday involving the traffic stop in Texas of a woman later found hanging dead in her jail cell showed how the incident quickly escalated into an altercation between her and a state trooper.

Sandra Bland, a 28-year-old black woman from the Chicago area, was pulled over on July 10 in Prairie View, Texas, northwest of Houston, for failing to signal a lane change.

The 52-minute video, released by the Texas Department of Public Safety, shows the trooper, Brian Encinia, approaching the car and asking if Bland is irritated. Bland replies that she is upset about being stopped for such a minor issue.

The conversation quickly turns hostile when the officer asks Bland to put out her cigarette and she asks why she can't smoke in her own car. The trooper then orders Bland to get out of the vehicle. She refuses, and he tells her she is under arrest.

At that point, the video shows Encinia demanding she leave the vehicle and then trying to pull her out. He then points a Taser and shouts: "I will light you up."

Bland asks at least 10 times about why she is being arrested and for what offense before Encinia replies she is resisting arrest.

She is heard telling the trooper: "I can't wait until we go to court."

Bland, who was taken into custody and later charged with assaulting an officer, was found hanging in her jail cell with a plastic trash bag around her neck three days later.

Her death was originally ruled a suicide. But her family, while acknowledging that Bland previously posted a video blog saying she was struggling with depression, has dismissed the idea she was suicidal. Family members said she was excited about starting a new job at her alma mater, Prairie View A&M University.

Waller County District Attorney Elton Mathis said on Monday he would investigate her death as a homicide. The state trooper, Encinia, has been put on desk duty for violating protocol in the arrest, officials have said.

Demonstrators have protested outside the jail where Bland died and her case has been taken up by activists who say it is the latest example of racial bias and excessive force by US law enforcement. The trooper involved in the incident is white.

Bland's family has called for an independent autopsy and involvement by the US Department of Justice in the probe of her death. A memorial for Bland was held at Prairie View A&M on Tuesday night attended by about 300 people.

"I am angry because of the way she died," Bland's mother, Geneva Reed-Veal, said at the memorial. "All I want to know is why."

Reuters - AP