The Deseret News reports Dr. Martin MacNeill was released Friday but remains on probation.
Utah County investigators and MacNeill's daughters believe he killed his wife in April 2007, then covered it up - charges the doctor has denied.
Michele MacNeill's body was found in a bathtub in the couple's Pleasant Grove home.
An autopsy indicated she died of natural causes, but a 2010 addendum to that report questioned the manner of death. Authorities now say they believe Michele MacNeill was drugged by her husband, but they haven't been able to prove it.
Martin MacNeill has never been charged in her death.
He served time after pleading guilty to fraudulently trying to obtain military, banking and Utah identification documents for another woman.
Information from: Deseret News
(Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)