Family and friends of a missing South Australian man have pleaded for the public's help as they struggle "with the unknown of the situation".
Ian "Reggie" Lees, 53, was last seen in Civic Park in Modbury on the night of February 28, and left his phone in the park.
He was then captured on CCTV footage walking on Fairleigh Avenue in Modbury North, in the direction of his house, in the early hours of the next morning.
He has not been heard from or used his bank accounts since.
SA Police has conducted a number of searches in the past six weeks and while his backpack was found on Fairleigh Avenue on March 11, they have not been able to locate Mr Lees.
Chief Inspector Paul Isherwood said police do not believe foul play was involved and said Mr Lees' disappearance was out of character.
"We're just hoping someone has some information about where he might be and we can locate him and make sure he's okay," Chief Inspector Isherwood said.
Mr Lees is described as 175 centimetres tall, of slim build, weighing 50 kilograms with grey hair.
He was believed to have been wearing a black Metallica T-shirt, black pants and black baseball cap.
Police have serious concerns for the welfare of Mr Lees, who suffers from a medical condition.
Mr Lees' niece, Grace Lees, urged anyone with information about the whereabouts of her uncle to come forward "no matter how minor the information may be".
"We are missing our uncle greatly and struggling with the unknown of the situation," she said in a statement.
"He is a lovely man, and we are very concerned.
Anyone with information should call Crimestoppers on 1800 333 00, or they can speak to police who will be stationed at the Woolworths entrance of Tea Tree Plaza until 8:00pm tonight.
