Police yesterday were trying to determine the motive of a killing in a church parking lot in Manoa.

Police arrested a suspect and say both the suspect and the victim appear to have been homeless.

The fatal beating occurred in the back parking lot of St. Pius X Catholic Church on Lowrey Avenue, possibly about 9 p.m. Tuesday, police said.

Police learned of the assault about 2 a.m. yesterday when David Orpin, 59, walked into the main station on Beretania Street, said Honolulu Police Department Capt. Britt Nishijo.

"The male reported that he had possibly killed a man in the church parking lot in the Manoa area," Nishijo said. "At that time, officers were sent to that parking lot and discovered a lifeless male."

Paramedics tried to revive the 70-year-old man, but pronounced him dead at the scene about 2:32 a.m.

The Honolulu Medical Examiner’s Office determined the victim died of head injuries from blunt force trauma. His identity remained unknown yesterday.

Orpin was booked at 2:35 a.m. on suspicion of second-degree murder. He was not charged yesterday.

Detectives were trying to determine why Orpin might have attacked the older man. Nishijo said detectives didn’t know of an argument beforehand and have not recovered a weapon.

"Everything is still under investigation, so we’re not sure if indeed a weapon is involved," he said.

Bloodstains remained on the ground in the church’s back parking lot yesterday afternoon.

A spokesman for the Catholic Church said homeless people have been known to sleep on the church grounds at 2821 Lowrey Ave., but no problems have been reported in the past.

Some residents reacted with surprise to the beating in the quiet neighborhood.

"I’m shocked because we don’t have that around here," said Manoa resident Tara Hathaway.

But residents have already grown accustomed to a few homeless people living in the upscale residential area. Neighbors of the church said a homeless woman parks her blue van on Lowrey Avenue, fronting the church.

Lynn Sato, a mail carrier whose route is in Manoa, said a few homeless people often walk from the park to the shopping center.

"I’ve noticed more over a year or so," she said.

Nadine Nishioka, a member of the Manoa Neighborhood Board, said although there are homeless people who live in the area, "they have not been a major problem."