Three members of the Wairoa Mongrel Mob are confirmed dead after their car crashed into the Mohaka River yesterday.
There might have been a second car involved in the crash, police said.
Police couldn't confirm if the members' car was forced off the road into Mohaka River, but said evidence from the scene suggested a blue Japanese car was involved.
The vehicle was carrying four Wairoa Mongrel Mob members on their way to the Mob's 50th anniversary celebrations in Hastings.
One person died at the scene, one was injured and two others were trapped in the car.
Officers are hoping the injured man, who was now out of hospital, would be able to help them find out what happened.
The police dive squad retrieved the two bodies from the river last night and this morning.
The names of the men involved in the crash have not yet been released.
Police wanted to speak to anyone who noticed any other vehicles near the viaduct between 2.30 and 2.45pm yesterday.
In another crash in the region, a motorcyclist was killed around 3.30pm today when his bike collided with a car at Te Haroto on State Highway 5, halfway between Napier and Taupo.