KITTERY -- The commander of a U.S. Coast Guard cutter was found dead aboard his vessel this morning.

Commander Keith Willis, 44, a native of Frisco, N.C., was found around 10 a.m. in the officer's cabin of the cutter Tahoma. The cutter was docked at its homeport, the Portsmouth Naval Shipyard in Kittery.

According to a statement from the Coast Guard, the cause of Willis' death is unknown.

The Tahoma had been most recently deployed off the New England coast where it conducted various law enforcement and marine safety missions. It returned to port on Jan. 28.

Members of the Naval Criminal Investigative Service and the Coast Guard Investigative Service are currently conducting an investigation on board the Tahoma.

Willis assumed command of the Tahoma in May 2007.