The 35-year-old off-duty Puna patrol officer was arrested in connection with drunken driving and negligent homicide.
Officer Kenneth Keliipio, 35, was taken to Hilo Hospital where he was pronounced dead at midnight following the 10:36 p.m. accident.
Colleagues today described Keliipio as conscientious, hard-working and well-liked by his peers.
"He always had a good sense of humor and solid sense of fair play and professionalism," said Sgt. Stephen Miller, who had met Keliipio, although they worked different shifts.
Keliipio, a 6-1/2-year police veteran, had picked up a stranded motorist and had turned left from Mamaki Street onto Volcano Highway, headed toward Keaau, when he was struck from behind by the off-duty officer's car, police said.
The off-duty officer, along with a 41-year-old woman who was a passenger in his car and the 29-year-old man in Keliipio's car, were in satisfactory condition at Hilo Hospital before they were released early today.
The passenger in Keliipio's car had called police after his family's car broke down. Keliipio responded to the call, picked up the man and was taking him back to his family when the accident occurred, police said.