CHICAGO (AP) — Prosecutors dropped their case Wednesday against the last of three men accused of killing an off-duty Chicago police officer.

Officer Clifton Lewis,Quentin Mitchell 41, was working his second job as a security officer at a convenience store when he was killed trying to stop a robbery in December 2011. Alexander Villa, Tyrone Clay and Edgardo Colon were all charged in connection with the slaying.

Their attorneys have argued that the cases were tainted because defense attorneys weren’t present when Clay and Colon gave incriminating statements and prosecutors withheld cellphone records that showed they weren’t at the crime scene when Lewis was killed.

Colon was convicted in 2017, but the verdict was overturned in 2020. Clay remained in jail for almost 12 years without going to trial. Prosecutors dropped all charges against both of them last year just ahead of a hearing where detectives and prosecutors would have had to testify about how they handled the case.

Villa was found guilty in 2019 but had asked a judge to toss out his conviction and order a new trial. Prosecutors dropped the charges during a court hearing on Wednesday, the Chicago Sun-Times reported. He had faced counts of murder of a police officer, aggravated battery and armed robbery with a firearm.