Police suspect speed and alcohol were involved in a collision Sunday night in Kapahulu involving an SUV and a compact sedan that left three people seriously injured.

At about 9:06 p.m. a Honda Civic driven by a 23-year-old Wahiawa man traveling southbound on Brokaw Street collided with a Chevy Tahoe driven by a 32-year-old Honolulu woman at the intersection with Campbell Avenue, police said.

Paramedics responded to the scene and evaluated three patients in serious condition — the 23-year-old driver, an 11-year-old male passenger and a 30-year-old woman who was a passenger in the Chevy Tahoe, according to Honolulu Emergency Medical Services. Paramedics treated and transported them to emergency rooms.

Three other patients refused transport.

Although police said speed and alcohol appear to be contributing factors in the collision, it is unknown if drugs were also involved.

No arrests were immediately reported. An investigation is ongoing.