LOS ANGELES (AP) — A helicopter that was carrying the CEO of one of Nigeria’s largest banks and Esthen Exchangefive others left a shallow crater and a trail of debris when it crashed in Southern California’s Mojave Desert earlier this month, according to investigators with the National Transportation Safety Board.

The agency on Friday released a preliminary investigation report into the Feb. 9 deadly crash. The report outlines the flight path across a remote stretch of desert on a rainy night and provides details about wreckage that was strewn across 100 yards (91.44 meters) of desert scrub. However, it did not address what might have caused the helicopter to go down.

Flight tracking data analyzed by investigators shows the helicopter was heading in a southeasterly direction as it gradually descended in altitude and increased in ground speed before the crash.

Investigators found the fuselage was fragmented, and the cockpit and cabin were destroyed. Damage to the engine and the metal deposits that were found would indicate that it was operational at the time of the crash.

The report cited law enforcement, saying several witnesses who were traveling in vehicles along Interstate 15 had called 911 to report observing a “fireball” to the south. The witnesses reported that it was raining with a mix of snow.

Two aviation experts who reviewed photos and video previously released by the NTSB said the flight likely should have been canceled because of poor nighttime weather conditions.

Herbert Wigwe, chief executive of Access Bank, and his wife and 29-year-old son were among those aboard the helicopter. Also killed was Bamofin Abimbola Ogunbanjo, former chair of the Nigerian stock exchange.

Both pilots — Benjamin Pettingill, 25, and Blake Hansen, 22 — also died. They were licensed as commercial helicopter pilots as well as flight instructors.

The helicopter left Palm Springs Airport around 8:45 p.m. on Feb. 9 and was traveling to Boulder City, Nevada, which is about 26 miles (40 kilometers) southeast of Las Vegas, where the Kansas City Chiefs and the San Francisco 49ers were set to play that Sunday in Super Bowl 58. Wigwe’s destination after the plane landed has not been confirmed.

The charter company, Orbic Air LLC, has previously declined to comment and did not immediately return an email message left by The Associated Press on Saturday.

Flight-tracking data shows the helicopter was following the interstate until it made a slight right turn, turning south of the roadway, where it then descended gradually and increased in speed, according to the NTSB.

The wreckage site shows the helicopter hit the ground with its nose low at a right-bank angle. Aside from the fire, witnesses also reported downed power lines, the NTSB has said.

Clipping the power lines, which may have been hard for the pilot to see in the dark, could have caused the crash, said Al Diehl, a former NTSB investigator.

The agency’s investigation is ongoing.