A Canadian nuclear scientist who has not been seen for more than a month has simply vanished, leaving "absolutely no trace at all," police say.

Lachlan Cranswick, 41, a physicist from the Chalk River Laboratories nuclear facility in Ottawa, was last seen on Jan. 18, when he left his job and boarded a bus to Deep River, his hometown along the Ottawa River with a population of roughly 4,300.

Later that day, or possibly the next morning, Cranswick took out the garbage -- and the single man described as a meticulous loner has not been seen since.

"It is open and there is nothing else we can do with it," said Const. Darin Faris, the Deep River police officer conducting the investigation. "Every bit of information, every lead that came in, everything ... has led us nowhere."

Faris said Cranswick's friends notified police of his disappearance six days after he was last seen, leading to fruitless searches of a 9-mile-long stretch of land along the Ottawa River. Helicopters, tracking dogs and civilians were unable to find a trace of the man.

Faris said investigators have no reason to believe Cranswick was targeted or that he was a victim of a crime.

"It's not like he's a reactor designer or that he knows how to use them," Faris told FoxNews.com. "He's not someone who, if you gave him highly enriched uranium, he could make a bomb. He's not that kind of person."

Investigators at first thought Cranswick had gotten lost while walking along several nearby trails, but every item he typically took on those trips -- at least two flashlights, a whistle and a GPS system -- was found in his unlocked home, along with his wallet, keys and passport.

"We don't believe he got lost," Faris said. "He's meticulous in all points of detail."

Faris acknowledged the possibility that Cranswick lost his way and fell through ice on the Ottawa River, or perhaps he was attacked by a wolf, coyote or bear, but investigators have found no evidence to support those theories.

"The average person would come to the conclusion -- it's not a good feeling," he said. "There's absolutely no evidence either way. There's absolutely no trace at all."

Daniel Banks, a colleague of Cranswick's at Chalk River Laboratories, said he saw no change in Cranswicks' demeanor prior to his disappearance.

"There was no indication he was going anywhere," Banks said. "Everyone has said that he seemed normal, especially during the time leading up to the disappearance."

Cranswick, an avid curler, specialized in conducting experiments in structural chemistry and Earth sciences, Banks said.

Anyone with information regarding Cranswick is requested to contact the Deep River Police Department at (613) 584-3500.