St. Clair County jurors found David Fields not guilty of the Dec. 30, 2016 murder of Carl Silas of Belleville.
Circuit Judge Robert Haida read the verdict at 9 p.m.
Fields was told he would be able to leave the courthouse without handcuffs to return to county jail - where he has spent the last two years - for out-processing.
But when he arrived back at the jail he was told he could not be released due to a parole violation.
Several of Fields' family members were present when the verdict was read, and some accompanied him back to jail where he had planned to gather his belongings and leave a free man.
Fields was represented by Brittany Kimble of Chicago and Ryan Neal of St. Louis.
He was prosecuted by Charles Colburn of the Appellate Prosecutor's Office.