A 23-year-old Port Orchard man was arrested early Saturday on suspicion of vehicular homicide after his car rear-ended a second vehicle, killing the driver, according to the State Patrol.

The accident happened just before 2 a.m. at state Highway 160 and Long Lake Road in South Kitsap County. The State Patrol said a 2003 Infiniti G35 driven by Peter Sedrak rear-ended a 1990 Geo Prizm driven by 52-year-old Harold L. Keith, of Port Orchard.

The impact forced the Prizm off the road, where it rolled down a 20-foot embankment.

Keith, who was wearing a seat belt, was pronounced dead at the scene, the Patrol said.

There were two passengers in the Infiniti. Sedrak's 27-year-old wife, Rachel Sedrak, was taken to Harrison Medical Center with neck and back injuries. The second passenger, Jeremy Dildy, 24, of Silverdale, called a friend to pick him up and drive him home. Detectives caught up with him a short time later and questioned him.

As troopers were investigating the collision, a hand grenade was seen near the vehicles, the State Patrol said. A bomb squad responded and determined the grenade to be an inert World War II-era "pineapple" grenade.

The road was closed for nearly 6 ½ hours for the investigation.

The State Patrol says alcohol and speed contributed to the crash.

Peter Sedrak is being held in Kitsap County Jail in lieu of $100,000 bail.