POCATELLO - The lead investigator of the unsolved Tom Sherwood murder says the case is frustrating because he believes he knows who the suspects are and has a motive in mind, but the key piece of evidence that could prove it in court remains elusive.

Andy Thomas, Bannock County Sheriff's detective, has worked the case since Sherwood was found dead in the basement of his home in September of 2000. He had been shot twice with a shotgun. Investigators initially ruled the death a suicide, but following a reconstruction of the scene, they determined it was a murder.

"I've worked this case for eight years now. It's a part of me," Thomas said Friday. "I would love nothing more in the world than to be able to bring closure to this investigation and be able to file charges."

Stephanie Sherwood, the victim's wife, offered a $10,000 reward for information leading to the arrest of those responsible for killing her husband. But since the early stages of the investigation, Thomas and his fellow detectives focused on Stephanie and her brother as people of interest in the case.

"I know who our suspects are in the case. It's just a matter of finding enough evidence to prosecute them. That's the frustrating part about it. We know what evidence we need for that to happen, and it hasn't happened yet," Thomas said. "We have had other people review the case, and it comes back to the same conclusion we came up with."

Thomas, a 23-year veteran of the sheriff's office, said that he keeps track of Sherwood's widow and brother-in-law. He knows where they live and work.

The detective said other people also know what happened, but until they come forward, the case will be tough to close.

"The nice thing about a murder case, if you can say there's any nice thing, is they never expire. There's no statute of limitation," Thomas said. "They are open for eternity until they are solved. There could be breaks, that one person who knows something who will give us the piece of the puzzle we need. And there's always the possibility of new technology helping us."