"We are still working to establish exactly what has occurred at the address and cannot rule out the possibility that further people were involved.
"We have received a number of a calls from members of the public and this is greatly appreciated."
One person remains in Auckland Hospital in a serious but stable condition, and a fifth person was released from Whangarei Hospital yesterday.
Rogers said police were following strong lines of enquiry. They earlier confirmed the Black Power and Nomad gangs were involved.
"We want to reassure our community that we still have a number of investigators working on this case.
"We continue to encourage our community to go about their business, but to contact us if they have any concerns," he said.
Anyone with information that can assist police with this case is asked to contact Whangarei Police Station on (09) 430 4500. Alternatively, information can be provided anonymously on 0800 555 111.