A manslaughter investigation is underway after an argument in Waipahu led to the death of a 61-year-old man.

The Honolulu Medical Examiner’s Office has yet to release the positive identification of the victim, however, a family member has identified him as Nelson Corpuz of Waipahu.

Police said 31-year-old Lanch Corpuz was involved in an argument with a man later identified as Nelson Corpuz at a residence at about 4:15 p.m. Monday when the dispute escalated and the suspect punched the victim.

Nelson Corpuz was taken in critical condition to a hospital where he died Tuesday morning.

Lt. Deena Thoemmes of the Honolulu Police Department’s Homicide Detail said preliminary autopsy findings indicate Corpuz died of “blunt force head injury.” His death has been classified as a homicide.

Police initially arrested Lanch Corpuz at the residence on suspicion of second-degree assault. The case was reclassified to manslaughter after Nelson Corpuz died. Lanch Corpuz has since been charged with manslaughter and remains in custody.