SPOKANE, Wash. --- Spokane County Sheriff’s Office is searching for a missing 39-year-old man who did not show up to work Tuesday and has not been seen since.

Family and friends of Nicholas R. Knowlton reached out to SCSO, according to a release, because that kind of behavior was unusual for him and “they are very concerned for his welfare.”

Knowlton’s family began to search for him Tuesday after he did not show up for work, and was not at his residence in North Spokane, SCSO said in a release.

“His family states, Knowlton has had some personal problems as of late, and coupled with this highly unusual behavior and disappearance, they fear for his safety,” SCSO officials wrote in a release.

Knowltown is a white male and 6’ tall. He weighs 395 lbs and has brown hair and brown eyes, according to officials.

He drives a silver 2005 Nissan Armada, with Washington plates AXT7296, which has not been located, SCSO reported.

Anyone who knows where Knowlton might be or has seen him is asked to call Crime Check at 509-456-2233 and reference #10061304.