A mentally-ill black inmate has lost his life in a prison cell in the US state of Virginia after four months of detention without bail.

Jamycheal Mitchell was arrested in Portsmouth, Virginia, on April 22 for stealing $5 worth of groceries, The Guardian reported on Saturday.

The 24-year-old was kept in custody without bail despite only facing misdemeanor charges.

His family members said they believed he starved to death after refusing meals and medication in Portsmouth.

“His body failed,” said Roxanne Adams, Mitchell’s aunt. “It is extraordinary. The person I saw deceased was not even the same person.”

Adams, a nurse, said Mitchell had practically no muscle mass left by the time he died.

Mitchell reportedly suffered from bipolar disorder and schizophrenia for about five years prior to his death.

A judge had ruled he was unfit to stand trial and asked for his transfer to the state mental health facility. But the hospital allegedly said it had no vacancy.

Police are now investigating the death as they wait for autopsy results. But prison officials say his death will not be treated as suspicious.

“As of right now it is deemed ‘natural causes’,” Natasha Perry, the master jail officer at the Hampton Roads regional jail in Portsmouth, said of his death.

She said there were no obvious outward signs of injury to his body.

African Americans are also far more likely to be arrested and imprisoned by police than any other racial group, according to an analysis by USA TODAY.

Experts say the dramatic gap in arrest and prison rates reflects biased policing as well as the vast economic and educational inequalities that plague much of the US.

The United States has suffered from an epidemic of racial violence throughout its history, which some experts say has increased after the election of President Barack Obama.