The search for Steven T. Koecher, who has been missing since Dec. 13, got a boost this week with a picture and description of the St. George resident appearing on milk cartons in some stores in the southern Utah city and in the Las Vegas area where he was last seen.

Police in Las Vegas and Henderson, Nev., have searched the desert near where a person believed to be Koecher was seen walking away from his car in an upscale neighborhood. But those searches turned up nothing on the 30-year-old.

"Why was he there is the million-dollar question," said his father, Rolf Koecher, on Monday. "It is surprising how he just disappeared. We looked at all the possibilities, not wanting to discount anything."

Koecher said his son was actively looking for work at the time of his disappearance, but was not despondent or acting in any way to suggest he might have committed suicide.

Family members are still searching the Las Vegas area, Koecher said. More than a week ago, they followed up on a tip that someone matching Steven's description was seen at a pancake restaurant.

"After talking to a worker at the restaurant we determined it wasn't him," Koecher said.

After Steven was reported missing, Koecher said family members checked with the hospitals, jails and even the morgue for several days.

"We've been through casinos, stores, restaurants and other areas," Koecher said. "We realized it was like looking for a needle in a big haystack. It [Las Vegas area] is just a huge place and even if he was there our chances of finding him are slim."

Keith Paul, a spokesman for the Henderson Police Department, said Monday that after Steven disappeared, the desert surrounding the area where the car was found was searched by police and volunteers on foot and by helicopter.

Paul said the case is still considered active and police are following up leads, but he was not specific.

"There is nothing to indicate foul play," said Paul.

Not knowing Steven's whereabouts has put a strain on the family, said Rolf Koecher.

"We struggle because we don't know if we should grieve or have hope," he said. "It's like a loss that goes on and on without resolution. On bad days we can hardly do anything because we're frozen in despair."

mhavnes@sltrib.com