Transcript for 8 American tourists killed in Mexico bus crash

We do have new developments in the deadly tour bus crash in Mexico. Several Americans are among the dead. Authorities confirming 12 people were killed during that trip to the mayan ruins. The number of Americans tourists dead stands at eight tonight. The victims traveling on a royal caribbean cruise ship out of Florida. A prosecutor now revealing the possible cause of that bus crash that followed. Pointing blame at the driver tonight. ABC's Victor Oquendo in Miami. Reporter: Tonight, the investigation into this deadly tour bus crash in Mexico that zeroing in on the driver. A state prosecutor revealing driver negligence and speed may be to blame for the accident that left at least 11 injured and killed 12. But say the driver could not be detained at this time. Among the dead, eight Americans, including 11-year-old Daniel, his mother Anna and grandmother. Sw him shaboro saw his relatives last before they left Florida for their cruise, his brother in law and one nephew survived -- I'm in shock, I'm still crying I can't believe it, I love my mother in law so much and I love my cousin and -- and I love them all. Reporter: According to Mexican officials, the bus, loaded with passengers from two ships left dock around 9:00 A.M. Tuesday on excursion to the mayan ruins. 30 minutes later, the bus crashing on this narrow two-lane road with no shoulder or guardrail. There were a lot of dead people on the floor. Reporter: Officials saying their preliminary investigation incads the bus driver's negligence may have led him to lose control before flipping, striking a tree and landing in vegetation along the side of the road. We just want to know what's going on. We just want an honest answer. Reporter: Mexican officials now launching a potential homicide investigation. So, let's get to Victor Oquendo from Miami. And Victor, what is the cruise line now saying tonight? Reporter: David, royal caribbean refusing to comment on the investigation. Both of their ships have continued with their itineraries as planned. Tonight, the U.S. Embassy in Mexico says it has staff at local hospitals to help with the victims and their families. David? Victor, thank you.

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