KUNIA — The search for a motorist who caused a devastating early morning crash by trying to pass in a no-passing lane continued last night in the aftermath of a deadly traffic accident that left four farm workers dead and injured eight others.

Officials yesterday put out a public appeal for witnesses, and although a civilian employee at Schofield Barracks was interviewed in their investigation, police were still seeking the motorist.

"The vehicle overtaking traffic was doing so illegally," said Honolulu Police Capt. Frank Fujii. "We need as much information as possible to try and piece together this tragic event. This person may be responsible for killing four people."

While police interviewed a 46-year-old civilian employee at Schofield Barracks as a possible suspect, he was not arrested nor was his car impounded. Police did not say if he was the driver of the four-door sedan that was trying to overtake traffic on the two-lane road.

The sedan is described as silver or light blue and fled the scene. It was last seen by witnesses who followed the car entering Schofield Barracks, Fujii said.

A failure-to-render-aid case has been opened and police pleaded last night for witnesses to the crash to call traffic investigators. The incident could prompt more serious criminal charges depending on witness statements, Fujii said.

Killed were four women in their 40s and 50s who were among at least 10 people riding in the bed of a red pickup that swerved into the path of a cement truck to avoid the oncoming sedan, police said. The cement truck struck the pickup head-on, throwing all of the passengers from the pickup bed.

A farm worker, who asked only to be identified as Tommy, told reporters as he was entering Larry Jefts Farms in Kunia that he was treated and released from the hospital after being thrown from the back of the pickup truck.

Wearing blue hospital clothing and braces on his legs, Tommy said all he could remember was hearing a loud screech before becoming unconscious when he was thrown from the back of the truck.

Officials with Larry Jefts Farms declined to comment.

All four women were pronounced dead at the scene, said Emergency Medical Services spokesman Bryan Cheplic. Cheplic also said there were no seat belts or other types of safety restraints in the bed of the truck, which was covered with a brown, canopy.

Of the eight truck passengers who were hospitalized, three were listed in critical condition, three were in serious condition and two were listed as stable as of yesterday afternoon, Cheplic said. Five of the injured are female, three are male. All were at The Queen's Medical Center.

Fujii said police did not know the identity of the owner of the red pickup.

The identities of the victims were not released yesterday.

Yesterday's deaths were a terrible addition to the dangerous reputation of Kunia Road, which about a year ago was the site of a crash that claimed the life of a father and two of his sons. As recently as last month, a father of two was killed in a single-vehicle accident on Kunia Road.

The crash also brought to mind a debate on whether the state should prohibit people from riding in the beds of pickup trucks, which is illegal for those 12 and under.

State officials said yesterday's crash was the worst involving people riding in the back of a pickup truck in the past 15 years.

With the four fatalities, the number of people killed in traffic accidents on O'ahu through yesterday has risen to 35, compared with 28 by the same time in 2005. Last year, 78 people were killed on O'ahu roads.

The accident occurred on Kunia Road near the Anonui Street entrance to the Royal Kunia subdivision at 7:35 a.m.

Police said the pickup was southbound when it tried to swerve out of the way of the sedan, which was northbound. The sedan had just tried to overtake other northbound traffic.

The pickup then collided with the cement truck, which was being driven by a man in his 30s, who was not injured. Officials with the cement truck company said the driver was declining comment.

The cement truck is owned by Island Ready-Mix Concrete Inc., which issued the following statement:

"Our hearts go out to the families of those involved in a terrible accident this morning that involved one of our concrete mixer vehicles.

"According to the information available to us, a truck carrying a number of workers collided with one of our vehicles. The police are involved in an extensive investigation and our driver has provided his own account of the circumstances that led the truck with the workers to veer into the oncoming lane and collide with our vehicle, apparently while trying to avoid a third vehicle."

More than 20 Honolulu firefighters assisted city Emergency Medical Services technicians in recovering bodies and tending to the injured. The accident closed Kunia Road for nearly seven hours as workers cleaned debris.

The two-lane Kunia Road runs between Waipahu and Wahiawa and is flanked by farm fields on either side. It has been the scene of several deadly crashes over the past half-dozen years.

Two solid double lines run from the Kunia interchange past Anonui Street and a sign that warns drivers not to pass in the area is clearly posted, said state Department of Transportation spokesman Scott Ishikawa. Fatal accidents in the area have occurred on upper Kunia Road in an area that allows drivers to overtake slower traffic.

"I've never heard of an incident of someone trying to overtake traffic on the lower portion of Kunia Road," he said.

"That's a double-solid yellow line. There should be absolutely no reason someone should be trying to overtake traffic if that is allegedly what happened," he said.

The red pickup truck's front end and windshield were smashed. It was hauled from the scene by a fork lift from a nearby farm.

The cement truck was hauled away just after 12:30 with a heavy duty tow truck. The road opened nearly two hours later.

One farm worker, 46-year-old Carlos Pancipanci, said he was cut off from getting to Larry Jefts Farms, where his shift was scheduled to start at noon yesterday. He said he recognized the pickup truck in the accident as one used to take farm workers to a tomato field near 'Ewa.

"Four people dead — that's shocking," Pancipanci said.

Reach Loren Moreno at lmoreno@honoluluadvertiser.com and Peter Boylan at pboylan@honoluluadvertiser.com.