Bill Gibbard is a character who appeared in the Season 5 episode "Mr. Monk, Private Eye".
Bill Gibbard was a charter boat captain who worked late hours. When questioned about the case, Gibbard denies seeing anything, and Monk feels the absence of Captain Stottlemeyer and Lieutenant Disher: without police backup, Monk has no authority to make anyone talk.
Later, Jay Bennett kills Bill and dumps his body in the water. The next day, Natalie hears Gibbard’s Dog barking and whining. She goes to see what’s wrong, and sees Bill’s body in the water.