Three days have passed since 15 year-old Allison Bayliss disappeared while riding her bike to San Ramon Valley High School. And now authorities have shifted their efforts from trying to find a missing person, to combing for a body, The San Jose Mercury News reports. Police now believe that Bayliss killed herself. San Francisco police Captain Lisa Locati told the Chronicle they believe Bayliss boarded a BART train at Dublin station, got off at Embarcadero, and rode her bike over to the Golden Gate Bridge. It was found there early Tuesday, after family members perused Bayliss’ computer and found the same route traced on Google Maps. Locati said the police have evidence that Bayliss walked onto the bridge, but never walked off.