Police were called to the address at 7pm and found Barton, known as Whiti, with critical injuries.
He was rushed to hospital and died soon after.
Detective Inspector Lex Bruning said he believed the people involved in the assault were known to Barton.
A scene examination at the Orchard St property was completed over the weekend and a second address in Motueka was also being combed by forensic teams today.
“We are confident in the progress made in our inquiries,” Bruning said of the property searches.
Police are still seeking the owner of a white BMW X5 station wagon with the registration BMW693.
“We believe this vehicle is of interest to the investigation and are seeking to locate it,” Bruning said.
“Police are working to determine exactly what happened. .. residents can expect to see an increased police presence in the area over the coming days.”
Anyone with information was encouraged to contact the police.
“Thank you to the public for their help and information provided to police to date,” he said.
Bruning said he had “a small, hard-working team” on the homicide investigation and they were “dedicated to piecing together the events that have unfolded leading up to Whitikau’s death in order to identify those responsible”.
“Our thoughts are with his family and police will work to support them through this difficult time as we investigate to give them answers,” he said.
“Staff from across the Tasman district will be adding to our efforts in the coming days to provide further assistance and support to the investigation team.
A post-mortem examination has been carried out and Barton’s body has been returned to his family.
Alternatively, information can be provided anonymously to Crime Stoppers on 0800 555 111.
Anna Leask is a Christchurch-based reporter who covers national crime and justice. She joined the Herald in 2008 and has worked as a journalist for 18 years. She writes, hosts and produces the award-winning podcast A Moment In Crime, released monthly on nzherald.co.nz