In Charleston, South Carolina, two white men are on trial - and the outcome of the cases could bring the local community to "boiling point", according to one black community leader.

Self-proclaimed white supremacist, Dylann Roof, who shot dead nine black churchgoers on 21 July 2015, faces the death penalty and 33 federal charges in federal court.

His case is entering final jury selection, with candidates being whittled down from more than 3,000 to just 12 jurors and six alternates. Starting Monday, groups of 10 people will be questioned in a court room and chosen by lawyers.

US district judge Richard Gergel said opening statements from prosecutors and defense lawyers might start later this month or in early December, and the trial could carry on until 2017 due to holidays.

Across the road in the municipal court, former North Charleston police officer Michael Slager is on trial for murder in the death of Walter Scott, an unarmed black man who was shot in the back in April 2015 as he ran away.

Scott reportedly ran away as he was worried about being jailed for not paying child support.

Due to the racial tensions surrounding both cases, local faith leaders, officials and the National Association for the Advancement of Colored People have pleaded for peace during the trials.

Walter Scott shooting video

Charleston Mayor John Tecklenburg told the Post and Courier: "I hope and believe we will be an inspiration to everyone not in just how to conduct a trial but in how we can constructively move forward and treat everyone with love and respect rather than hate."

But leaders among the black community were not convinced.

Dot Scott, president of the NAACP Charleston branch, told The Independent that the 11 jurors in the Slager case are white, and there is one African American man who claimed under questioning he had not even heard of the victim and had not seen the video of police shooting him in the back.

"These two cases were totally different in terms of number of deaths, but not so different in terms of the intensity of feeling - here was one person, Dylann, who took away nine lives, but in the Slager case, it was our own government."

She said the case of Slager was equally important to the trial of Roof, as one, to some extent, influenced the other.

"Young people like Dylann get the message that those black don’t lives don’t matter, there is a perception of inferiority and racial bating and the continuous message that their lives don’t mean anything," she said.

Referring to ineffective policing and government, she said: “You’ve been feeding them monsters, you’ve grown us to this level of distrust and built up anxiety and frustration, and it comes to boiling point."