Taiwanese prosecutors have closed their investigation into a July bus crash that killed all 26 people on board, including 23 Chinese tourists, saying the driver was suicidal.

Taiwan's Central News Agency reported Saturday that authorities could not find an electrical problem or other cause for the bus catching fire. Prosecutors said the driver of the bus had planned to kill himself, purchasing gasoline to pour inside the bus and drinking before the crash.

Including a Chinese tour guide, 24 of the people on the bus were visiting Taiwan from China's Liaoning province.

It was the deadliest single incident involving Chinese tourists since Taiwan began admitting mainland visitors in 2008.