WASHINGTON — Navy criminal authorities are investigating whether two members of the Navy’s elite SEAL Team 6 strangled an Army Green Beret on assignment in Mali in June, military officials say.

Staff Sergeant Logan J. Melgar, a 34-year-old veteran of two deployments to Afghanistan, was found dead on June 4 in the embassy housing he shared in the Malian capital, Bamako, with several other Special Operations forces.

The service members were assigned to the West African nation to help with training and counterterrorism missions.

The soldier’s superiors in Stuttgart, Germany, almost immediately suspected foul play, and dispatched an investigating officer to the scene within 24 hours, military officials said.

Agents from the Army’s Criminal Investigation Command spent months on the case before handing it off last month to the Naval Criminal Investigative Service.

No one has been charged in Melgar’s death, which a military medical examiner ruled to be a homicide — strangulation, said three military officials briefed on the autopsy results.

The two Navy SEALs, who have not been identified, were flown out of Mali soon after the episode and were placed on administrative leave.

The death has been shrouded in mystery, and the biggest unanswered question is why Melgar was killed.

“NCIS does not discuss the details of ongoing investigations,’’ Ed Buice, the agency’s spokesman, said in an e-mail, confirming that his agency took over the case on Sept. 25.

Neither the Army nor the military’s Africa Command issued a statement about Melgar’s death, not even after investigators changed their characterization of the two SEALs from “witnesses’’ to “persons of interest,’’ meaning they were trying to determine what the commandos knew about the crime and if they were involved.

When contacted separately Saturday, Melgar’s widow, Michelle, and his brother, Shawn, declined to comment.

The uncertainty has left soldiers in the tight-knit Green Beret community to speculate whether the killing might have been the result of a personal dispute among housemates gone horribly wrong or whether Melgar might have stumbled upon some illicit activity the SEALs were involved in, and they silenced him.

Revelations about Melgar’s death surface against the backdrop of four US soldiers killed in an ambush in neighboring Niger this month while conducting what initially was a reconnaissance patrol but later shifted unexpectedly to supporting a more dangerous counterterrorism mission.