The investigation into the death of Whanganui man James Butler is "large and complex", police say.
No arrests have been made, but Detective Inspector Ross McKay told the Chronicle on Tuesday police were following strong lines of inquiry.
"The investigation is large and complex and will take some time," he said.
"At this stage no charges or arrests have been made in relation to the death of James."
Butler was found dead at a Wikitoria Rd property on the evening of April 22.
Meanwhile, another man in his 50s, who was found seriously injured at the scene, has since been treated and discharged from hospital.
Police launched a homicide investigation following the incident and last week the National Dive Squad was called in to search the Whanganui River while police carried out forensic examinations at the scene.
Police were hoping to find weapons the offenders involved in Butler's death may have discarded.
Last Wednesday police revealed the death of the 53-year-old Butler was not the result of a random attack and people in the incident were known to each other.
Anyone who may have information which could assist in this investigation was asked to contact police.
Information can be given anonymously by calling Crimestoppers on 0800 555 111.