The body of U.S. Marine from Coal City, southwest of Chicago, was found under the flight path of an aircraft after he apparently fell out during a training exercise.
Steven Hancock, a 2nd Marine Aircraft Wing Marine, was found late Tuesday afternoon.
Hancock's MV-22B Osprey aircraft was conducting a training flight Monday evening when the Marine disappeared about 45 miles west of Marine Corps Air Station New River, near Jacksonville, North Carolina.
Personnel on board the aircraft with Hancock on Monday told NBC News they weren't immediately aware that Hancock had fallen out a cargo door.
"We did not learn of his fall immediately and we are not sure why," 1st Lt. Hector Alejandro, spokesman for the 2nd Marine Aircraft Wing, told NBC News on Wednesday. "It's going to be investigated. It is unfortunate the length of time it took, and honestly we don't know how long that was."
Friends say Hancock died doing what he loved. His Coal City High School principal, Mitchell Hamann, said he died doing what he loved.
For those who knew him, that was always a goal. He was an Eagle Scout, which right there describes what kid was ... the character he has," Hamann said.
Hancock joined the service after graduating in 2011.
"He was a quiet leader," school district superintendent Kent Bugg said. "His senior year he got involved in our GABC program and our welding program. You can tell what kind of kid he was to be going to serve his country in the Marines. He was just a top quality kid from a good family."
Hancock would have turned 21 this week. His death comes at what would have otherwise been a happy time for his family.
"It really was a shock and it hit close to home for the school district. His older sister Julia graduated from here. His younger sister Mallory graduated on Sunday and his mother is an aide with us in the special ed department working with our special needs students," Bugg said.
"When we have a loss of one of our graduates, it is like we lost a member of our family as well," Hamann said.