The trial of a Baltimore police officer charged in the 2015 death of black detainee Freddie Gray is set for closing arguments on Thursday, with a decision to come early next week in the high-profile case.

Officer Edward Nero, 30, is the second officer to go on trial in Baltimore City Circuit Court over Gray's death from a broken neck suffered while in custody inside a police van.

Gray's death in April 2015 triggered rioting and protests in the majority-black U.S. Middle Atlantic city. It was also a key incident in fueling the Black Lives Matter movement.

Nero was among three bicycle officers who chased Gray, 25, after he fled unprovoked in a high-crime area. Gray was arrested and bundled into the transport van while shackled, but was not seatbelted in place as required by department policy.

During the week-long trial, prosecutors contended that Nero pursued Gray without probable cause and failed to secure Gray in the van.

But lawyers for Nero have argued that he was ill-trained in securing detainees. They also say he had little to do with Gray's arrest and never touched him except when he tried to help him find an asthma inhaler.

He faces misdemeanor charges of second-degree assault, reckless endangerment and misconduct.

Nero waived his right to a jury trial and Judge Barry Williams is deciding the case in a bench trial. He has said he will issue his decision on Monday.

Officer Garrett Miller, Nero's partner, testified on Monday that he was the officer who arrested Gray.

Nero is among six officers charged in Gray's death. The charges against the others range from misconduct in office to second-degree murder.

The trial of the first officer involved in the Gray case, William Porter, ended in a hung jury in December.

(Writing by Ian Simpson in Washington, editing by G Crosse)