Big Island police have opened a negligent homicide investigation into a car crash that killed a Waimea couple and their 5-year-old boy late Saturday.

The couple's 8-year-old daughter was injured in the two-car, head-on collision on Highway 19 near Mana Road. A 47-year Kea'au man also was injured.

Speed and alcohol appear to be factors in the crash, police said.

According to police at the Waimea station, the accident was reported at 11:48 p.m. after a Chevrolet station wagon, with the family of four inside, and a sport utility vehicle collided head-on on Highway 19.

Police said the driver of the Chevrolet, a 32-year-old Waimea man, crossed the center line and collided with the Mercury SUV, driven by the Kea'au man.

Police identified the woman killed in the Chevrolet as Suzanne Ng, 30. The boy was identified as Aidon Ng, 5. Authorities yesterday had not identified the 32-year-old Waimea man who was driving the Chevrolet.

But Suzanne Ng's sister, Kristen Castro, said the driver of the Chevrolet station wagon was her sister's boyfriend, Brandon Ng, and the children had his last name. She identified her sister as Suzanne Leong.

Castro also identified the 8-year-old girl in the crash as Aimee Ng.

Aimee was at The Queen's Medical Center yesterday, Castro said, and may need surgery but was expected to recover from her injuries.

Castro said the couple and their children were returning from a friend's birthday party when the accident occurred.

Yesterday afternoon, Castro and other family members placed flowers at the accident site.

Police said they arrived at the scene of the crash about 11:54 p.m. Saturday.

When they got there, the Kea'au man was in critical condition in the roadway, after apparently being thrown from his vehicle.

The Waimea couple was pinned in the front seats of the station wagon, and their two children, the 5-year-old boy and the 8-year-old girl, were in the back seat.

Rescuers used the Jaws of Life to remove the victims from the vehicle.

The couple and boy were pronounced dead at North Hawai'i Community Hospital.

The Kea'au man was taken to Queen's in guarded condition, police said.

A vehicle fire at the accident scene had been put out with portable extinguishers when police arrived.

The two-lane highway where the crash happened was closed for hours early yesterday so police could investigate.

The crash happened soon after another fatal crash on the Big Island on Saturday, which killed Hawai'i football player Jesse Mahelona.

Mahelona, 26, who had a brief NFL career, was killed about 1 a.m. Saturday when the Honda sedan he was driving struck a concrete barrier and construction equipment.

Police said he was pronounced dead at the scene of the Kailua, Kona, crash.

Alcohol may have been a factor in that crash.