Nightly News | April 13, 2014
>>> new details are emerging tonight in the investigation into that fiery bus crash in northern california . nbc's janet shamlian has more from willow, california. janet, good evening.
>> reporter: hi, carl. what is left of the bus and the truck have been moved here. investigators aren't close to being done with them. but they have learned more about this horrific accident. an important clue from the charred shell of the bus. investigators have found the black box -type device. but the more critical one from the fed ex truck was incinerated in the fire.
>> we can look at aspects of steering and other pieces that did survive to possibly get a sense of the speed range and the revolutions of the wheels, to maybe even know the direction they were in.
>> reporter: the ntsb says this were no skid marks from the fed ex truck, indicating the driver never hit the brakes. did he fall asleep or suffer a health problem? investigators are looking at everything, including cell phone records and his schedule the 72 hours before the crash. blood samples were taken from both drivers, sent for alcohol and drug testing .
>> i could hear screams of people who were trapped inside burning alive. they were screaming "help me, i don't want to die."
>> reporter: vivid memories from miles hill , who is covered in burns. the 18-year-old was sitting right behind the bus driver and saw the truck coming directly at them. there have been some reports that the other truck, the fed ex truck, was actually in flames as it crossed the median. did you see anything?
>> it was not in flames. it was in perfect condition. it exploded upon impact on the bus.
>> reporter: the ntsb tonight concurs, saying there is no physical evidence yet.
>> what that means in the overall investigation we're not ruling anything out.
>> reporter: a small memorial along the interstate is the only physical sign here of the tragedy. the scars now are mostly out of view. families of those who died planning memorials, and survivors just trying to hold on. a handful of high schools will be without one of their classmates in the morning. they are in the los angeles area , and those schools are providing counselors to the friends left behind .