“Island County Sheriff’s investigators say they are looking for a man who may have information on the recent drowning death of an Oak Harbor man.The body of Russell L. Kunkel, 47, was found on a beach near Whidbey Island Naval Air Station on Dec. 19, clad only in one workboot and sock. Investigators believe he drowned sometime between Dec. 17 and 19, but don’t know how he entered the water.No one is sure yet, Sheriff Mike Hawley said Tuesday, but “there’s just enough there to let us suspect there might have been foul play.’’According to a Sheriff’s Department press release, the man sought by detectives is not a suspect, but was reportedly seen with Kunkel in the days that preceded his death. The “person of interest’’ depicted in a Sheriff’s Department sketch, is a white man about 25 to 30 years old, about six feet tall with a slender build and short, dark, well-groomed hair. He wears wire-rim glasses and possibly a dark or black jeans-style jacket.Anyone with information can call 360-679-9567.”