A tour bus catches fire on highway to the Taiwan Taoyuan International Airport in Taiwan, July 19, 2016. [Photo by China Times/Asianewsphoto]

TAIPEI -- Driver of the bus that caught fire in Taiwan on July 19, which killed 26 people, has been confirmed to be driving under the influence of alcohol, local authorities said Friday.

Everyone on board the bus was killed when it crashed into a highway barrier and caught fire near Taoyuan Airport. They included 23 tourists and a tour guide from the Chinese mainland, a local driver and a local tour guide.

The tourists were on their way to the airport to return home after an eight-day visit when the accident happened.

Earlier investigation has found that five plastic bottles filled with gasoline may have exacerbated a bus fire.

Investigators maintained that human error may have caused or worsened the inferno.