Detectives have released CCTV footage of a missing man on the last day he was seen.
Craig Alderson, who is originally from the Queensbury area, has not been seen since January 20.
The 44-year-old has not been in touch with any friends or family, despite repeated appeals via the media.
Detective Chief Inspector Chris Gibson, of Calderdale Police, said: "We hope that releasing these new images and video of Craig that they might jog someone's memory and members of the public can assist us in trying to trace him.
"It is extremely out of character for Craig to go missing and for him not to be in contact with his friends and family.
The CCTV images were captured in Chapel Street, Queensbury, at around 10.45pm on 20 January.
They show Mr Alderson holding a laser measuring device in his hand.
Officers in Calderdale have been conducting extensive enquiries to locate Craig, both in residential areas and open ground, working alongside local Search and Rescue teams and partners across both Bradford and Calderdale districts.
They have also been continually in touch with Craig's family, friends and acquaintances.
Det Chief Insp Gibson said: "We have been conducting extensive enquiries for the last month to locate him.
"I firmly believe that the answers to finding Craig lay within the Queensbury area, and once again to appeal to anyone who thinks they may have seen him, or anyone who has heard from him or knows where he is now to get in contact with the police.
"We are ever increasingly concerned for Craig's welfare and our investigation is ongoing as we continue to strongly urge anyone who has any information to come forward as soon as possible."
Any information about Craig's whereabouts should be passed to police by calling 101, quoting 13170034270.