One motorcyclist was killed and another critically injured yesterday afternoon when their motorcycles struck a rental van on Kailua Road, forcing the closure of the main road into Kailua during a sunny Sunday afternoon.

According to the Honolulu Police Department's Traffic Division, the maroon Chevrolet van, driven by a Japanese national, was traveling north in the right lane of Kailua Road, near Ulu'oa Street, when it turned into the left lane — occupied by the motorcyclists — to reach a grassy median used for U-turns.

The two motorcyclists, who were in group with three other riders, locked their brakes but were unable to avoid hitting the van, HPD said.

A 46-year-old man was taken to Castle Medical Center, where he later died. The other rider, described as a male in his 40s, was taken to The Queen's Medical Center in critical condition.

The driver of the van did not appear to be injured, according to Honolulu fire Capt. Terry Seelig.

Police are investigating whether speed was a factor in the collision. HPD said alcohol does not appear to have been a factor.

Molly Arthur, 37, was at the nearby YMCA Windward Branch, where she works as a swim instructor, when she heard the crash just after 2 p.m. She and a co-worker then ran across busy Kailua Road to the scene of the crash.

One of the victims had stopped breathing and had no pulse, so Arthur performed cardiopulmonary resuscitation.

"He was really messed up," she said. "His face was bloody and his shirt was torn."

Arthur said she performed CPR for "five to 10 minutes" before Emergency Medical Service workers took over.

Arthur said the man gasped a couple of times while she was working on him, and she was told by EMS workers that the man's pulse returned.

It was the first time Arthur has had to perform CPR. Her previous certification expired, but she is in the process of renewing it. She was still shaken by the incident a couple of hours later.

"I'd never given CPR before, and I'd never even seen an accident before," she said. "I'd never seen anything like that in my life."

Police halted Kailua-bound traffic from Ulu'oa Street for more than three hours to conduct their investigation, with traffic diverted to Kalaniana'ole Highway from Pali Highway.