Migrant on packed cargo truck says vehicle was "speeding" before crash that killed dozens in Mexico

Authorities are looking into whether speed was a factor into a deadly truck crash in southern Mexico.  

A migrant from Guatemala said he was among 200 people aboard a cargo truck when the truck tried to make a sharp turn. The sheer weight of everyone inside and the speed that the truck was going caused the truck to tip over and roll—crashing into a pedestrian bridge, according to the migrant.  

"The truck was speeding," he said.