So I'll address the elephant in the room, which is most people who travel to the bridge and then disappear near or on it have jumped over it. It is well covered by CCTV and human surveillance. It is curious that there has been no mention of what LE is doing to investigate - has any of this footage been looked at (I have to think it has). I also wonder if they know he went over and haven't told the family until they can recover his body. According to wikipedia, the barrier project is still not completed, so there is no net in place. Less than 25% of people who jump are recovered. The Missing Pieces flyer says he was seen again by a passing motorist around 9:30pm near the parking lot on the Marin County side, disoriented and walking in the direction of ' the tunnel' so he was potentially around there for 4+ hours. So which tunnel?
What about his phone, student ID, drivers license? Did he drive there and leave a car? Does he have roomates or a dorm, and has anyone turned on his computer or tried to access his facebook messages? (It sounds like he left a home where his sister was)
Here is a Facebook page for him:
Come Home, Gavin