Two decades after Ohio State medical student Brian Shaffer walked into a campus bar and vanished, the mystery that has gripped central Ohio remains unsolved — and investigators say someone still knows what happened. Shaffer, 27, was last seen April 1, 2006, when he went out to the Ugly Tuna Saloona near the Ohio State campus. Surveillance video captured him inside the bar, but he was not seen on camera leaving. When his friends were ready to go, they could not find him and left without him.