Keisuke Koizumi was 22 when he was last seen in San Francisco on April 23, 2008, while attending a language school. He left the hotel room he shared with another student, saying he would deliver a computer monitor to a friend, and never returned. All of his belongings remained in the room.

There are concerns he may have been suffering from depression and possibly taking anti-depressant medication at the time. He was last seen wearing a white long-sleeved t-shirt, a gray argyle sweater, a light-colored olive green jacket, blue jeans, and white Converse sneakers. The San Francisco Police Department continues to handle the case, but very few leads have been developed.

If anyone knew Keisuke, his friends in San Francisco, or remembers seeing someone matching his description on or after April 23, 2008, please come forward with information.