Military investigators picked through the charred wreckage of a Marine Corps cargo plane Tuesday, seeking clues on why it spiraled out of the sky in western Mississippi, killing 16 military personnel, said a Marine statement.

The probe into Monday’s crash of the KC-130 aircraft, en route from Marine Corps Air Station Cherry Point, N.C., was ongoing, the Marine statement added. The plane is used for refueling and carrying cargo and troops.

The names of those killed were not immediately made public pending notification of family members, the Marine statement said.

Mississippi Emergency Management Agency Director Lee Smithson told the Clarion-Ledger that the aircraft crashed on the Leflore-Sunflower county line, a rural stretch of woods and fields with dense underbrush and vegetation about 85 miles north of Jackson. Earlier, Sheriff Ricky Banks told the Ledger that five of the crew members were confirmed dead. It is unclear where the plane took off from.

Andy Jones, a local resident, told the Associated Press that he was working on his family’s catfish farm just before 4 p.m. when he heard a boom and looked up to see the plane corkscrewing downward with one engine smoking.

“You looked up and you saw the plane twirling around,” he said. “It was spinning down.”

He told the AP the plane hit the ground behind some trees in a soybean field, and by the time he and other reached the crash site, fires were burning too intensely to approach the wreckage. The force of the crash nearly flattened the plane, Jones said.

“Beans are about waist-high, and there wasn’t much sticking out above the beans,” he said.

Pictures posted to Facebook and published by the Ledger showed thick black smoke coming from a field. The debris field appears to span a large area.

The KC-130 is a four-engine propeller-driven aircraft that is a variant of the Cold War-era C-130 Hercules. The plane can be configured to refuel aircraft in midair or equipment on the ground. It can also haul troops and equipment and in some cases carry an array of weapons.

Brian Murphy contributed to this report.