Five of the six Baltimore police officers charged in the death of Freddie Gray are fighting to take down the Maryland state attorney who announced the charges – and they want to take the fight all the way to the Supreme Court.

In 2016, two officers were acquitted, another’s trial resulted in a hung jury, and prosecutors dropped charges against the remaining three officers. It was an emotional end to the case that had gripped the city of Baltimore ever since April 2015 when Gray, a 25-year-old black man, died from a spinal injury he suffered in the back of a police van, and the death was ruled a homicide.

After the state charges were dropped, five of the exonerated officers tried to sue state attorney Marilyn Mosby for malicious prosecution, defamation and invasion of privacy. But the Virginia appellate court handling the suit found that Mosby, who took office in 2015, was protected by prosecutorial immunity. Prosecutorial immunity is meant to shield prosecutors from being sued for their actions in a case.

Now, the officers want the Supreme Court to reconsider the application of that immunity.

Gray’s hospitalization and subsequent death sparked violent protests in Baltimore. Protesters looted businesses and burned a CVS, which led to Maryland Gov. Larry Hogan declaring a state of emergency and deploying the National Guard.

Just 11 days after Gray’s death, Mosby made an impassioned plea to protesters and, vowing justice, announced a slew of criminal charges against the officers.

Activists hailed her as a hero. Critics, including the law enforcement community, accused her of playing politics with the case to bolster her own popularity and political ambitions. The Fraternal Order of Police called the hastily-filed charges an “egregious rush to judgement.” In an op-ed for the Baltimore Sun, a former deputy state’s attorney for Baltimore suggested that Mosby’s decision was a “calculated push to the spotlight.”

In addition to the suit filed by five Baltimore officers, a George Washington University law professor filed an ethics complaint against Mosby in 2016 with the Maryland Attorney Grievance Commission, calling her a “runaway prosecutor” and saying she proceeded with criminal charges against the officers without probable cause.