A sailor assigned to the attack submarine Helena died late last month after being electrocuted aboard the boat, officials have confirmed.

Sonar Technician Submarine 3rd Class Timothy Sanders, 22, was found deceased while the ship was at the pier aboard Naval Station Norfolk, Virginia, on May 24, according to Naval Submarine Force Atlantic officials.

The Naval Criminal Investigative Service is investigating Sanders’ death, and the Navy has declined to provide further details, citing ongoing investigations.

“We deeply mourn the loss of our shipmate, and our thoughts and prayers are with the sailor’s family, friends and coworkers during this difficult time,” Navy spokesman Cmdr. Jason Fischer said in a statement. “Grief counseling services and support are being provided through the chain of command and local chaplain resources.”

Known to his family as Timmy, Sanders’ obituary describes him as the “favorite uncle” among his niece and nephews. The obituary also says he had an infectious smile, and that his presence “brightened every occasion.”

“Timmy loved his service to the Navy, loved being a sailor and loved his ship mates like family,” his obituary states. “He had recently reenlisted, his dream was to one day be master chief.”

“Timmy was always filled with honor and had a moral code that had no gray area,” the obituary adds. “We were not surprised when he chose the Navy.”

Sanders is survived by his fiancé, his parents, four sisters, six nephews and one niece, as well as many cousins, aunts, uncles and grandparents.

“His absence will leave our family forever incomplete,” the obituary states.