DeJarnette, 59, pleaded guilty in March to killing Yu DeJarnette in 2006. Initially he had told police he had gone to look for her after waking up during the night to find she was not in the house and found her, injured, at a lava outcropping near their home on the Big Island.
An autopsy determined Yu DeJarnette died of blows from a tire iron, the Los Angeles Times reported.
Daniel DeJarnette was arrested at the time but was released due to insufficient evidence.
When the case was reviewed in January 2012, deputy prosecutor Linda Walton was able to use blood evidence linking Daniel DeJarnette to the slaying, as well as evidence indicating he had tried to clean up blood in the house, the Times said.
He was arrested and charged in May 2012.
Daniel DeJarnette joined the Los Angeles Police Department in 1982 and retired in 2003. He worked in homicide in Van Nuys and the Robbery Homicide Division-Rape Special Section, and moved to Hawaii after he retired.