Police investigating the death of Bram Willems, in Bay of Islands, are appealing for witnesses to an altercation before his death

Willems died in Opua on 7 January from fatal stab wounds.

Detective Senior Sergeant Geoff McCarthy says a woman who witnessed an altercation on nearby Kawakawa's main street has spoken with Police.

Police believe there was another altercation, at the Bay of Islands College bus bay between 10-past-10 and 11 o'clock that night.

McCarthy says anyone who witnessed the altercation or saw a silver Toyota Altezza vehicle, registered MQE620, should contact Police.

A 14-year-old has been charged with murder in relation to Willems' death, and is due in the High Court at Whangarei on February 4.