angeles. >> reporter: some people called 911 just seconds after the crash, other people were literally on the phone with dispatchers when the bus exploded into a massive fireball. this all happened last thursday on i-5 in northern california. the fedex truck barreled across the median, crashed head on into a bus filled with high school students who were headed to humboldt college. the bus ended up exploding, ten people died, five students, three adult chaperones, the fedex truck driver and the tour bus driver all killed. listen to one panicked student describe the aftermath of the crash to a dispatcher. >> you still on the bus, or are you off the bus with at this point? >> everyone's off the bus. the bus is on fire. >> i understand. are you away from it, or are you still on it? >> yeah. we're getting away from the bus actually. >> okay. >> reporter: investigators say right now they're not speculating as to what caused the crash. what they are doing is recreating the scene. they brought out two of the same vehicles to safely recreate the