The death toll now stands at 15 in the crash of a charter bus that skidded off a freeway north of Dallas.
Federal investigators say the blown tire on a charter bus that crashed and killed 15 people had been refitted with a new tread in violation of safety standards.
The National Transportation and Safety Board also said late
Friday that the driver of the bus was a 52 year old who had a
commercial license but whose medical certification had expired.
Authorities say the bus was operating illegally early Friday when the right front tire blew.
The bus smashed into a guardrail and tipped over.
Authorities say 12 people died at the scene, and three others at Dallas-area hospitals.
The bus was carrying a Vietnamese Catholic group from Houston to
an annual pilgrimage in Missouri.