Oakland police say Jonathan Bandabaila disappeared May 3.
His family says he was driving to a soccer tournament at the time, and he had plans to attend a formal dance.
His 1998 Honda Accord was found parked on the San Mateo bridge.
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Bandabaila's brother says the search has taken a heavy toll on both he and his family.
"And they don't see me cry much. Yet every time I come forth to speak about this situation I try so hard to stand still, stand tall, stand strong, and I can't stay composed yet I do know that my brother's out there. And I do feel one hundred percent that he'll come home and we'll find him," said Harrison Bandabaila
Police are asking anyone with information on Jonathan Bandabaila to call a special 24-hour hotline at 510-238-3641.
The search continues for missing person Jonathan Bandabaila, 20, from Oakland. Last seen May 3, 2019. Missing Persons/Special Victims Unit & Bandabaila family passing out flyers, Cities of San Leandro, Hayward & San Lorenzo cell phone showed in the area. pic.twitter.com/wDkDvTewjT— Oakland Police Dept. (@oaklandpoliceca) January 5, 2020