Searches have resumed in the Cave Hill area of Belfast for missing local man Michael Cullen, who hasn't been heard from in four days.
Family and friends say they are growing increasingly worried for the 33-year-old.
They last heard from him at about 2pm on Tuesday.
Brothers Rory and Loius Girvan, who are close friends of Michael, told UTV his disappearance had been tough to cope with.
“This is totally out of character – it doesn’t seem like something he would do,” Louis said.
Rory added: “The family are being incredibly strong and incredibly practical – every day, we’re just doing absolutely everything we can.”
Volunteers are aiming to search the entire Cave Hill Forest Park.
Flyers are also being distributed in the Boucher Road and Lisburn Road areas of south Belfast after some suggestions Michael may have been in those areas prior to his disappearance.
When last seen, he was wearing a dark green parka, grey jumper and black jeans.
He is described as being 5ft 9ins tall and of thin build, with short dark brown hair and brown eyes.
Anyone who knows of Michael’s whereabouts, or who has any information, is asked to contact police on the 101 number.