The investigation by Manawatu police into the disappearance of Hansen was upgraded to a homicide inquiry earlier today.
"Based on information that we have received in the past 12 hours we have upgraded this inquiry to a homicide investigation," Detective Senior Sergeant Simon Harrison said this morning.
"While I am not prepared to divulge the nature of the information for investigative reasons, this is a significant turning point for our investigation and this information has further confirmed our serious concerns around Mr Hansen's disappearance."
Mr Hansen, 48, has been missing since November 24, when police say he was seen driving a grey primer-coloured 1980 Ford ute, registration JM9538.
The vehicle was located at a property in Linton last Thursday. Armed guards have been posted outside the house where officers have been carrying out a scene examination for some days.
Police still do not know who is responsible for Mr Hansen's disappearance but every effort is being made to answers to these questions, Mr Harrison said.
"We are continuing to make inquiries and one of our main focuses is on locating Mr Hansen so we can return him to his family."
To date no-one has been arrested in relation to Mr Hansen's death but police are keeping an open mind as to who is responsible.
"To protect the integrity of our inquiries I will not be making any comment on individuals of interest to this investigation."
Police are making good progress with the scene examination at the Linton property and today a team of 10 officers supported by ESR staff will continue the examination.
"Officers working on the investigation have been encouraged by the support from the public, and we are still keen to hear from anyone that may have any information about sightings of the vehicle or any other information that could assist us with our investigation," Mr Harrison said.
Anyone with information is asked to contact Detective Dave Wilson (06) 213 9595. Information can also be provided anonymously to Crimestoppers on 0800 555 111.
