The National Transportation Safety Board has issued its preliminary report about the April 10 crash between a FedEx Freight truck and a bus in California killing 10.

It outlines events leading up to the crash and gives no indication to the cause. “The information in the report is preliminary and will be supplemented or corrected during the course of the investigation,” said NTSB.

According to the report, the crash happened about 5:40 p.m., local time, when, a 2007 Volvo truck tractor with two 28-foot trailers was traveling southbound in the right lane of Interstate 5 in Orland, California. At the same time, a 2014 motor coach operated by Silverado Stages, occupied by a driver, 43 high school students, and three adult chaperones was traveling northbound on I-5 in the right traffic lane.

“In the vicinity of milepost 26.02, the FedEx combination vehicle moved to the left, departing the southbound traffic lanes and entering the 58-foot wide center median. The vehicle drove through a line of oleander bushes in the center of the median and entered the northbound traffic lanes of I-5,” said the report. “It collided with the left rear portion of a white 2013 Nissan Altima four-door passenger car, occupied by a driver and one passenger, which had just passed the Sentra motor coach and moved back into the right lane of northbound I-5. The Nissan rotated counterclockwise and departed the highway on the east side. Following the impact with the passenger car, the combination vehicle collided with the motor coach, and both vehicles departed the highway to the east.”

NTSB said a post-crash fire then occurred, but it made no mention of eyewitness reports that claimed the truck was on fire before the crash happened. In the days just after the crash, NTSB investigators said they found no evidence to support such claims.

The drivers of both the FedEx Freight truck and motor coach were killed. Eight motor coach passengers were also fatally injured. The remaining passengers received injuries of varying degree. A total of 46 passengers were on the bus. The occupants of the Nissan passenger car received minor injuries.

NTSB said its investigation has determined the FedEx Freight truck originally departed from the FedEx facility in Sacramento, Calif., at about 10:00 a.m. and drove to Weeds, Calif., approximately 49 miles south of the Oregon border, where the driver delivered two trailers. At about 3:30 p.m., the driver picked up two other 28-foot trailers and was en route back to Sacramento when the accident occurred.

The motor coach, part of a chartered trip originating from Los Angeles, Calif., was taking high school students to Humboldt University, in Arcata, Calif., for a tour of the campus. The motor coach had made a scheduled stop in Sacramento, where a replacement driver took over operation of the vehicle.

It will likely be several months before NTSB issues its final report as to the cause of the crash.

Just a few days ago the first known lawsuit stemming from the crash was filed. The $100 million negligence suit was filed in Los Angeles by the attorney representing the mother of a 17-year-old who was one of five students on board the bus that were killed. It names the estate of the FedEx truck driver and the company that owned the bus as defendants.