Authorities on Sunday recovered the last remains of six people killed when a Puerto Rico National Guard helicopter plummeted into the ocean en route to a drug raid last month.

The remains of Carlos Acevedo were found along the coast of Loiza, a beach community near the U.S. island's capital of San Juan, said National Guard Gen. Antonio Vicens.

Acevedo was one of the pilots of the National Guard's UH-72 Lakota helicopter that crashed Dec. 20.

"Now Acevedo's family and the National Guard of Puerto Rico will be able to bury this valiant man," Vicens said in a statement.

Crews have already found the bodies of Col. Victor Torres Rodriguez, who was second in command of the Puerto Rico National Guard; Sgt. Jose Omar Sostre; pilot Hector Ramierez; and prosecutors Mario Torres Marin and Francisco Mujica de Leon.

Federal officials are investigating the cause of the crash, which happened as those aboard headed toward the outlying island of Vieques to oversee a drug raid. Two other helicopters on the same mission encountered heavy rain but reported no problems.

The helicopter was bought in May 2009 and received regular maintenance, the National Guard has said.