PINEDALE (WNE) — A Pinedale man who went swimming off a boat during an employee appreciation party on Fremont Lake Wednesday afternoon was presumed dead after he failed to resurface. 

His body was not found by press time. 

Thursday, Tip Top Search and Rescue volunteers continued to search for Richard “Rick” DeRuiter Zylker, 52, who was celebrating with the Ridley’s Family Market group. 

At some point people realized he disappeared from the surface, in Moosehead Bay, one of the farthest inlets to Fremont Lake, according to Sublette County Sheriff KC Lehr. 

The search for the missing man continued with a side-scan sonar boat manned by John Linn. The search was based at Fremont Lake Campground’s upper boat ramp, which was closed to parking. The lake was not closed for public use. 

Fremont Lake’s frigid water is usually 55 to 65 degrees and 200 to 300 feet deep in the bay, according to officials there. 

Ridley’s store owner Mark Ridley, who was at the Pinedale store on Thursday, declined to comment out of consideration for Zylker’s fellow employees and family. 

Although Zylker was still considered “missing” at press time, he is presumed to have drowned or died from as of yet unknown medical causes, said Sheriff Lehr.