Investigators are trying to determine what caused the first crash of the deadly multi-vehicle accident on Interstate 75 South of Gainesville, CBS News is reporting. Ten people were killed, while another 18 were hospitalized, in the January 29, 2012 crash, which may turn into a criminal investigation. The accident scene ran for one mile on both sides of I-75, with the remains of up to 19 vehicles littered down the entire stretch.

The visibility was so poor that initially, rescuers could locate victims only by their screams. Alachua County Sheriff spokesperson Sadie Darnell said “It was a very traumatic situation…Hearing crashes, hearing explosions, hearing people scream.”

The accident was in part caused by a combination of zero-visibility conditions, from fog and smoke. The fog is believed to have come from a nearby brush fire, which is suspected to have been set intentionally. Officials can’t find a natural cause for the fire, like a lightening strike.

Investigators are also going to question why the interstate had reopened after it had been closed, due to the mixture of fog and heavy smoke from the brush fire. All lanes of I-75 reopened after the accident, but closed during the early morning of January 30, due to poor visibility from the fog and smoke.

Written by: Karen Benardello