New police chief for Ferguson

The mayor of Ferguson, Missouri has appointed a new police chief, nearly a year after the police shooting of unarmed black man Michael Brown sparked weeks of violent protests.

Interim chief Andre Anderson, who is black, pledged on Wednesday to instill the force with the "respect, cultural awareness and the professionalism this community deserves."

The appointment comes as racial tensions remain high across the United States in the wake of a series of high-profile cases of African Americans being killed by police in disputed circumstances.

The latest case is that of a black man killed by a University of Cincinnati police officer during a traffic stop on Sunday.

The family of Samuel Dubose, 43, joined protesters at a rally on campus on Tuesday demanding answers and access to video footage from the officer's body camera and nearby buildings, the Cincinnati Enquirer reported.

"Why can't I see the video," his nine-year-old son said.

Dubose was killed after he was pulled over for a missing front licence plate, the paper said.

He produced a bottle of alcohol when asked for his driver's licence and then struggled with police officer Ray Tensing at the door of the car.

Tensing, who had bruised legs and a torn uniform, fired one shot which killed Dubose.

The death of a black woman who was found hanged in her cell days after being arrested during a traffic stop in Texas is being investigated as suspicious after her family insisted Sandra Bland had no reason to kill herself.

A dash cam video of the arrest released on Tuesday shows a white officer arguing with Bland, pulling out his taser and saying "I will light you up" after she refuses to put out her cigarette and get out of the car.

Rebuilding the trust between police and the African American community is a national project, Anderson said after his appointment was announced in Ferguson.