The Alameda County Sheriff's Office reported a male was making bomb threats via his cellphone on social media. The cellphone was in the area of the Embarcadero Station. Officers checked the area with negative results. Dispatch was advised a short time later that the male was at our Daly City Station. Officers detained the male on a train at the Daly City Station. A patron later alerted officers that there was an unattended backpack on the same train. The train was held at the San Francisco Airport, the train was evacuated along with the station. After the train was searched and deemed safe, the station was reopened. The male was placed on a psychiatric hold, with a criminal hold for terrorist threats and false bomb threats. There were no direct threats made towards the BART system. TSOC was notified.