A Baltimore judge on Monday acquitted another police officer charged in the death of Freddie Gray.

Baltimore Circuit Court Judge Barry Williams cleared Lt. Brian Rice, the highest-ranking Baltimore Police Department officer charged by Baltimore State Attorney Marilyn Mosby, of involuntary manslaughter, reckless endangerment, and misconduct.

The judge heard closing arguments last week.

Gray, a 25-year-old Black man, died of a spinal injury he suffered after being taken into police custody in April 2015. His death sparked widespread protests and helped inspire a number of reforms, including an effort by local grassroots activists to allow citizens on police trial boards. The boards, introduced in the 1990s, make decisions about disciplining officers that can be affirmed or reversed by the police commissioner.

Mosby sought to hold Rice responsible for failing to secure Gray in a seat belt while riding in a police transport van following his arrest.

But Williams, according to a Baltimore Sun report, said prosecutors failed to prove the elements of the crimes and wanted him to rely on “presumptions or assumptions.”

Williams had dismissed a second-degree assault charge midway through the trial, while the state had dropped a misconduct charge after recognizing Rice was not directly involved in Gray’s arrest, according to the Sun.

Rice, who is white, is the fourth officer out of six charged by Mosby to go to trial. His trial represents the third acquittal in connection to Gray’s death. Williams cleared officers Edward Nero and Caesar R. Goodson Jr. in May and June, respectively.

The first trial, concerning Officer William Porter, ended in a hung jury, or mistrial, in December. Porter’s second trial is scheduled to begin on September 6. The trial of Officer Garrett E. Miller is slated to begin July 27; Sgt. Alicia D. White, October 13.

All officers charged by Mosby pleaded not guilty.

Closing arguments in Rice’s bench trial came on Thursday, the same day officials from the American Civil Liberties Union of Maryland and the Campaign for Justice, Safety, and Jobs (CJSJ) announced they had filed friend-of-the-court briefs on July 14 in an effort to dismiss a lawsuit filed by Baltimore’s police union, the Fraternal Order of Police Lodge 3.

The union had filed the lawsuit in an attempt to prevent the police department from providing internal affairs police records to Baltimore’s civilian review board.

The CJSJ, which is a coalition of grassroots groups and national organizations like Baltimore United for Change, the Baltimore Algebra Project, and Amnesty International, said the union lawsuit is an effort to block “institutional changes leading to police accountability and transparency.” The coalition’s leadership argued that the suit would disable the “civilian review board from carrying out its responsibility in bringing much-needed transparency to Baltimore policing.”

The union had opposed the reform efforts because the proposed changes would allow citizens who lacked “specialized knowledge” about policing to review internal matters, according to the Sun.