BOSTON (AP) – A man who was about to a go on trial for a second time pleaded guilty in a 1995 slaying that sent the wrong man to prison.

John Tibbs pleaded guilty to manslaughter Monday, admitting he shot and killed 17-year-old Tennyson Drakes. Sentencing was set for Tuesday.

Marlon Passley was sentenced to life in prison for the crime after being convicted of first-degree murder in Drakes’ death in 1996. Passley served four years in prison before Suffolk County prosecutors exonerated him after learning from a drug dealer that Tibbs was the shooter.

Tibbs’ first trial ended in a mistrial last year after the jury deadlocked.

Tibbs is currently serving a 27-year federal prison sentence in the 1995 killing of Steven Sealey, a friend of singer Bobby Brown.

AP-ES-01-07-08 1640EST