A patron reported that there was a subject who walking down the consist claiming that here was a bomb on-board the train. The reporting party advised that the suspect stated this somewhere between the Macarthur and 19th St. Stations. The train was held at the Hayward Station and the station, platforms, and train was briefly evacuated. The train was searched by officers, a sergeant, and a K9 officer searched the train consist with negative results. The train was held at the station for approximately 40 minutes. The suspect was described as a Black male in his 40’s, slim build, short black hair, wearing a burgundy flannel shirt, and black jeans. TSOC was notified.