An inmate at a Michigan prison, who turned down a chance for parole earlier this year, has died from complications caused by the coronavirus.

William Garrison could have left prison weeks ago after serving a 44-year sentence, but decided to wait until September when he would be eligible for release without parole supervision.

The Associated Press reported that Mr Garrison changed his stance when the coronavirus outbreak hit. The parole board approved his application in March, but he died on Monday during the mandatory 28-day waiting period before release.

Mr Garrison was found gasping for air by his cellmate at Macomb Correctional Facility.

Chris Gautz, a spokesperson for the Michigan Department of Corrections, said that Mr Garrison hadn’t previously complained to staff about his health.

Staff performed CPR on Mr Garrison and he was transported to hospital where he was pronounced dead. A postmortem test confirmed he was positive for Covid-19.

Mr Gautz described the situation as “unfortunate all the way around”.

“We came back to him and told him we would still like to parole him given his age and our concern with him getting the virus,” said Mr Gautz.

Mr Garrison agreed to be paroled and the Department of Corrections asked prosecutors to waive the waiting period. They did not respond before his death on 13 April.

“We did everything we could to get him out,” Mr Gautz said.

Mr Garrison was sentenced to life in prison for killing a man during a 1976 robbery when he was just 16 years old.

His sentence was reduced to 40 years in January as a result of US Supreme Court decisions making juvenile lifers eligible for release.

“He was a zealous advocate for himself and for other incarcerated persons. He often helped other individuals with their legal matters,” said attorney Becky Hahn, who helped Garrison get the reduced sentence.

The Detroit Free Press reports that more than 520 prisoners have tested positive for Covid-19, 78 out of them at Macomb. A total of 805 prisoners have been tested.

Michigan has 38,000 prisoners under the jurisdiction of the Department of Corrections.

As of Monday, Michigan has 31,424 confirmed cases of the coronavirus, and 2,391 recorded deaths. To date, it is one of the worst affected states — fifth in total number of cases and third in recorded deaths.