The Cambridge police department is continuing to investigate a public suicide on Wednesday. Police say a man walked into County Coins And Collectibles on the Southgate Parkway in Cambridge. The man spoke briefly with the clerk, asked for change for a soda machine, then exited the store. A few moments later, the man returned, went to the back of the store and removed a shotgun from the rack. Cambridge police says the man loaded the gun with a single shell and shot himself. The man is identified is 28-year-old Michael A. Yanda. He was pronounced dead at the scene by the county cororner. Several people witnessed the shooting, but no other injuries were reported.