Image copyright Reuters Image caption Officer Caesar Goodson drove the van in which Mr Gray rode before he died

Baltimore police officer Caesar Goodson has been found not guilty in his trial for the murder of black detainee Freddie Gray.

He was cleared on a second-degree "depraved heart" murder charge, the most serious charge sought against the six officers charged in the case.

Mr Goodson drove the van in which Mr Gray rode before he died.

The verdict is a blow to prosecutors, who have yet to win a conviction connected to Mr Gray's death.

Freddie Gray, 25, was arrested in April 2015 for running away from police officers. He died a week after sustaining a spinal injury while in the back of a police van.

His death sparked civil unrest in Baltimore, part of a wider national debate on police brutality and the death of unarmed black men at the hands of police.

Image copyright Murphy, Falcon & Murphy Image caption Freddie Gray died a week after he was arrested

At the end of the five-day trial, Baltimore Circuit Judge Barry Williams also acquitted Mr Goodson on charges of manslaughter, assault, misconduct in office and reckless endangerment.

The judge said the state had failed to show that Mr Goodson was aware he had injured Mr Gray or that he needed medical care.

Prosecutors had argued that Mr Goodson was criminally negligent when he failed to use a seat belt to secure Mr Gray and intentionally gave him a "rough ride" while transporting him to the police station.

The van made six stops during the ride to the police station. Mr Goodson was the only officer present at each of the stops.

"The state had a duty to show the defendant corruptly failed in his duty, not just that he made a mistake," the judge said in his ruling.

The same judge cleared another officer on misdemeanour charges in May and declared a mistrial in December after a jury failed to agree on charges relating to Mr Gray's death.

Image copyright Andrew Burton/Getty Images Image caption Freddie Gray's death last April sparked mass protests throughout Baltimore

Two further police officers are due to stand trial next month - one of them is charged with manslaughter.

A blow to campaigners - Rajini Vaidyanathan, BBC News, Baltimore

The verdict will be a blow to protesters and campaigners who have been calling for accountability. Two police officers have already faced trial in connection with Freddie Gray's death, but so far there have been no convictions.

The aftermath of his death, and the protests that followed, came to represent the fractured relationship between police and young black men. Last year's violent protests in Baltimore were the climax of anger and frustration which had been under the surface in the city for decades.

The judge says there was no intent to harm anyone in this case - but campaigners will want to make sure Freddie Gray's death was not in vain.

Mr Goodson hugged and shook hands with supporters and family members, including the officer acquitted in May, the Baltimore Sun reported.

State Sen Catherine Pugh, the Democratic nominee to become Baltimore's next mayor, issued a statement urging calm.

Protesters outside the courthouse began marching toward police headquarters after the verdict.

Image copyright Twitter

Baltimore Mayor Stephanie Rawlings-Blake responded via Twitter, saying Mr Goodson would face an administrative review and asked citizens to be patient.

Civil rights leader Reverend Al Sharpton said he was "disappointed" in the judge's decision.

The NAACP, one of the leading US civil rights groups, also called the verdict a "wake-up call for Baltimore".

Image copyright Twitter