Police arrested a 20-year-old driver whose three passengers were killed in a head-on collision in Nanakuli on Dec. 28.

The suspect was driving a Honda Civic that crossed the center line on Farrington Highway and crashed into a Nissan pickup truck carrying four people. Police determined that speed was a factor in the incident.

The driver’s 18-year-old girlfriend, their 1-year-old daughter, and the driver’s 19-year-old cousin were killed in the collision.

The driver was arrested Monday at the Kapolei Police Station on suspicion of three counts of first-degree negligent homicide and second-degree negligent injury. He was later released pending further investigation.