U.S. Navy SEAL Candidate Died from Pneumonia After 'Hell Week,' Officers Facing Administrative Actions

Obituary Kyle Mullen

Eight months after the death of a U.S. Navy SEAL candidate, the Naval Special Warfare Command released the results of their internal investigation.

The NSWC's investigation concluded the death of Mullen was "in the line of duty, not due to his own misconduct." Mullen died of acute pneumonia with cardiomegaly as a contributing factor, according to the Armed Forces Medical Examiner's autopsy report. He died just hours after successfully completing "Hell Week."

"Our deepest sympathy extends to Seaman Mullen's family and friends during this difficult time," Rear Adm. Keith Davids, Commander, Naval Special Warfare Command, said in a statement.

"Kyle's death will not be in vain," Davids said. "We have a moral obligation to learn everything we can from Kyle's tragic death so that we can ensure the safety of all future candidates."

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In response to the investigation, several officers and senior staff faced administrative action.

"Administrative actions have been taken regarding the former Commanding Officer of Basic Training Command, Capt. Bradley Geary, the Commander of Naval Special Warfare Center, Capt. Brian Drechsler, and senior medical staff under their command," a Naval Special Warfare spokesperson tells PEOPLE. "Those actions will be reviewed during the on-going Naval Education and Training Command investigation."

Mullen — who was once a football player at Yale University and Monmouth University — was pronounced dead at the Sharp Coronado Hospital in San Diego in February, the Navy announced in a press release at the time.

Williams Paul/Icon Sportswire/Getty Kyle Mullen

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Mullen, 24, and his Basic Underwater Demolition SEAL (BUD/S) class had just completed Hell Week, which is when sailors who wish to become SEALs go through intense training that pushes them to their physical and mental limits.

"Mullen was not actively training at the time of his death," the Navy said.

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After news of Mullen's death was made public, many who knew the young man paid tribute to him on social media.

Monmouth University's head football coach, Kevin Callahan, wrote in a tribute on Facebook, "We are all saddened by the unfortunate passing of Kyle Mullen. As a member of our 2019 championship team, he will be remembered not just as a[n] excellent player, but also as an excellent person and a great teammate."

According to NBC News, "about one in five" individuals who take part in the "Hell Week" training are able to make it through to completion.

The outlet reported that the course produces around 200 to 250 SEALs each year. The last candidate to die during training was 21-year-old James Lovelace, ABC News reported. The outlet said he drowned in a pool during the course in May 2016.