Police say a prison guard is a person of interest in the disappearance of Christchurch man Michael McGrath.
A scene examination is underway at David Benbow's property, who works as a guard at Christchurch Men's Prison.
Police say Mr Benbow is "a person of interest who needs to be eliminated from the inquiry".
They have been at the cordoned off property on Candys Rd in Halswell, Christchurch on Thursday conducting forensic examinations.
A number of other properties have been searched as part of the investigation.
Mr McGrath was last seen on May 21.
Police confirmed on Wednesday they have serious concerns for his wellbeing.
"Investigations this week, including speaking with his family and friends and the scene examination at Michael's home address in Checketts Avenue, indicate that his absence is completely out of character," a police spokesperson said.
Police are urging anyone who has seen Mr McGrath's blue 1994 Subaru station wagon over the weekend of May 21 through to May 23 to come forward.
They would also like to hear from anyone that Mr McGrath has completed any contract building work for over that period.