An unidentified Navy sailor was charged with negligent homicide in the death of Petty Officer Third Class Lyndon Joel Cosgriff-Flax, a 22-year-old master at arms assigned to Naval Weapons Station Yorktown, Va. (Max Lonzanida/U.S. Navy)

An unidentified Navy sailor was charged with negligent homicide last week in the death of a fellow sailor during a reported man overboard incident in Virginia, service officials said.

The sailor was charged in the death of 22-year-old Petty Officer Third Class Lyndon Joel Cosgriff-Flax, a master at arms assigned to Naval Weapons Station Yorktown, Va. The unnamed sailor, also assigned to the Yorktown station, is facing additional charges of making a false official statement and two counts of dereliction of duty, Navy Region Mid-Atlantic said Monday.

The charges date back to an April 28 harbor security boating incident that resulted in the death of Cosgriff-Flax.

Cosgriff-Flax, assigned to the installation’s security department, was participating in a training and area familiarization exercise on the York River at the time of his death. Officials initially reported he had fallen overboard but provided few details as the investigation was ongoing.

A court proceeding for the unnamed sailor charged in Cosgriff-Flax’s death has not yet been scheduled, the Navy said.

In July, the Yorktown station held a memorial for Cosgriff-Flax, according to the naval station.

Ensign Patrick Moore, Naval Weapons Station Yorktown’s security officer, provided remarks about serving with Cosgriff-Flax, including how the young sailor shared his mother’s cookies with members of the security department and his many jokes.

“These memories of [Cosgriff-Flax], like footsteps in the eternal sands of time, will never wash away and will be forever cherished because he served with us,” Moore said.

Cosgriff-Flax was a Kansas native who enlisted in the Navy in August 2021 and reported for duty at Yorktown in February 2022.