Peter Wlasiuk of Oxford is serving 25 years to life in state prison for 2nd degree murder.
Prosecutors say Wlasiuk's wife, 35 year old Patricia, was killed at the couple's home in Oxford, and driven to Guilford Lake in a truck her husband then pushed into the water.
Wlasiuk claims his wife was driving, and swerved to avoid hitting a deer, crashing into the lake and drowning.
A state Appeals Court found the trial was not fair
It says a vehicle accident study, given to the jury, was hearsay and shouldn't have been used as evidence.
The court also faulted the prosecutor, Joseph McBride for making derogatory statements about Wlasiuk,and presenting a vehicle accident study as hearsay evidence.