Pend Oreille County, WASH. -- It's been two years since anyone has seen or heard from 50-year-old Marty Lang. It's a case that has stumped investigators and torn apart the many loved ones left behind.

"Hell is an understatement for what we've been going through," said Marty Lang's son Thomas Lang. "I wouldn't wish this kind of pain on anybody."

Thomas was one of the many volunteers who came out to Marty's home just off of Scotia Road to look for clues. The property is located in a rural, heavily wooded area just outside of Newport.

Just before he vanished, Marty had picked up the two dogs he shared with his girlfriend. When he failed to return them, or answer any calls, everyone became extremely worried.

"I don't think he just went missing," Thomas said. "He did not wander off in the woods. My dad was a survivalist. He was prepped and ready for any situation that could come his way. I know he didn't just up and (leave.) He would never put me through that."

On the final day Marty had contact with his loved ones, he was just getting off work. He drove a truck for an asphalt company. Evidence shows he cashed a paycheck and then went to renew his driver's license.

"It came in the mail a few weeks after he disappeared," Thomas said. "Yeah, that was hard."

Marty then picked up the dogs and was said to be in good spirits.

"He loved those dogs," his girlfriend Lois Whitten told KHQ in 2018. "I think they know what happened. He would never just leave them out like that."

She said Marty was a tough guy, but those dogs brought out his nurturing side. Both Lois and Thomas say Marty was dependable. He was a hard worker, loyal, and a man of his word.

"He was strict by his morals," Thomas said. "He was a man's man. The kind we just don't have anymore."

Thomas said his dad loved living where he did. He enjoyed the peace and quiet. Now, he fears perhaps it was too quiet. The kind of place where someone could get away with murder.

"Absolutely, this was a murder," he said. "I don't think it was just one single person that did this. He always carried his Glock. I think it was at least two or more people."

Thomas has two theories on how it went down.

"I think that he either knew his killer(s) and he let them in, or whoever did it caught him off guard," he said. "He wouldn't let just anybody in. He wasn't the friendliest of people."

The scene yielded very little, but one thing has troubled Marty's family. His lunch box and water bottle were set down just a few feet, maybe less, from Marty's driver's side door. Almost as if he had to set them down in a hurry to deal with... something.

"My dad was the most OCD person you could ever meet when it came to being clean," Thomas said. "The lunchbox being there showed me he was not at his home for more than a few minutes whenever what happened, happened. He would never leave his lunchbox out like that, in the sun after a hard day's work. Never."

The metal cable that covered the driveway to access Mary's home had also been secured. There were no signs of a struggle.

It's a case that has left the Pend Oreille County Sheriff's Office hitting dead end after dead end.

Sheriff Glen Blakeslee was just elected last year. When this happened, he was working patrol and responded to the scene. He too remembers immediately making note of the lunchbox placement. He knew it was strange.

"It's a very unusual case," he said. "We found a couple of things that were oddities we wanted to document to see if they meant anything, but we found nothing that would lead us to a conclusion on what happened to Marty Lang."

While Marty's friends and family suspect foul play, investigators say they can't say one way or another. It's as if Marty Lang vanished into thin air.

"We did ground searches starting close to the scene and working the way out," he said. "We had a lot of people out there. We had individuals looking for tracks."

Sheriff Blakeslee said when they arrived at Marty's home, one of his dogs was there but the other was missing. They asked neighbors for help, and within a day or two, the other dog was found wandering the area.

"We know he was attached to those dogs, yes," he said.

The department called in extra resources. They brought out cadaver dogs, used drones, and even had Spokane County's helicopter fly over the area. All of it turned up nothing.

"We were not able to come up with a scenario that was more likely than another, we still don't know," the sheriff said.

Both the deputies and the family are hopeful they will find out what happened to Marty.

Thomas pleads with anyone who can help to do the right thing.

"I hope to God someone who knows something, even anonymously, will speak up and say something," he said.

Recently, Marty's mother passed away. Thomas said it was agonizing for her to know she would die without answers.

"Everyday the pain is just as real as the day this happened,' he said. "Somedays it's even much worse because it's been going on so long."

If you have any information regarding Lang or his whereabouts, please call the Sheriff's Office at 1-800-669-3407.