PHOENIX - Each day Detective Stuart Somershoe walks into his office and down a long hallway.

Its walls are filled with pictures of the faces of those who have disappeared,

“These are the ones we need to work on and get answers for,” Somershoe said.

His job is one of the toughest in the Phoenix Police Department: attempting to solve the cases of missing persons whose families are desperate for answers.

“This is a pain that doesn’t go away for them," he said. "Every birthday, every holiday, every anniversary is just like re-opening the wound for them."

Somershoe is a member of a team that numbers just five. Only five detectives try to find out what happened to the nearly 200 people that adorn the walls of their office. Many of their cases lack a crime scene, witnesses or any evidence at all.

“Technology in missing persons cold cases is not really part of our tool box, I guess you would say, because we lack evidence,” Somershoe said.

So then, how do you find out what happened to all these people?

Much of it, detectives say, is old school police work dating back centuries. In many cases, police hope that as time passes, a new voice comes forward.

“We don’t have a scene, we don’t have a body, that sort of thing," Somershoe said. "So, we really rely on relationship changes, and witnesses coming forward that didn’t talk before. We look for a person’s life pattern. And even homeless people have a life pattern. We are creatures of habit. We do the same things over and over again."

When there is an unidentified body, police try to get a match through DNA. But, with many of the missing, that often isn’t an option. Somershoe says he keeps the pictures on the wall, as a motivator.

"Kind of as a reminder," he said. "We have a duty to give answers to all these people and get justice for them if they’ve been a victim of a homicide."