No one has been charged in Sergeant Melgarâs death, which a military medical examiner ruled to be âa homicide by asphyxiation,â or strangulation, said three military officials briefed on the autopsy results. The two Navy SEALs, who have not been identified, were flown out of Mali shortly after the episode and were placed on administrative leave.
The biggest unanswered question is why Sergeant Melgar was killed. âN.C.I.S. does not discuss the details of ongoing investigations,â Ed Buice, the agencyâs spokesman, said in an email, confirming that his service had taken over the case on Sept. 25.
Neither the Army nor the militaryâs Africa Command issued a statement about Sergeant Melgarâs death, not even after investigators changed their description of the two SEALs from âwitnessesâ to âpersons of interest,â meaning the authorities were trying to determine what the commandos knew about the death and if they were involved.
The uncertainty has left soldiers in the tight-knit Green Beret community to speculate wildly about any number of possible motives, from whether it was a personal dispute among housemates gone horribly wrong to whether Sergeant Melgar had stumbled upon some illicit activity the SEALs were involved in, and they silenced him, according to interviews with troops and their families. Other officials briefed on the inquiry said they had heard no suggestion that the Navy commandos had been doing anything illegal.
When contacted separately by telephone on Saturday, Sergeant Melgarâs widow, Michelle, and his brother, Shawn, declined to comment.
Lawmakers have criticized top officers and Pentagon officials for offering a shifting timeline of the events in the Niger attack, and for failing to respond with timely, accurate information about the American militaryâs role on the continent at a time when President Trump has loosened restrictions on the armed forces to intensify attacks against the Islamic State and Al Qaeda around the world.
Sergeant Melgar, a graduate of Texas Tech University who joined the Army in 2012, was assigned to the 3rd Special Forces Group, based at Fort Bragg, N.C., the same unit whose soldiers were attacked by a much larger and heavily armed group of Islamic State fighters near the border between Niger and Mali on Oct. 4.
According to military officials, Sergeant Melgar was part of a small team in Bamako assigned to help provide intelligence about Islamic militancies in Mali to the United States ambassador there, Paul A. Folmsbee, to protect American personnel against attacks. The sergeant also helped assess which Malian Army troops might be trained and equipped to build a counterterrorism force.
Sergeant Melgar, a native of Lubbock, Tex., was about four months into what military officials said was a six-month tour in Mali, and was living with three other American Special Operations troops in a house provided by the American Embassy.
Two of those housemates were members of the Navyâs SEAL Team 6, which has over the past decade carried out kill-or-capture missions in Libya, Yemen, Afghanistan, Iraq and Somalia, as well as the one that killed bin Laden in Abbottabad, Pakistan, in 2011.
According to two senior American military officials, the two SEAL commandos were in Mali with the approval of Mr. Folmsbee in a previously undisclosed and unusual clandestine mission to support French and Malian counterterrorism forces battling Al Qaedaâs branch in North and West Africa, known as Al Qaeda in the Islamic Maghreb, as well as smaller cells aligned with Al Qaeda or the Islamic State. The Americans helped provide intelligence for missions, and had participated in at least two such operations in Mali this year before Sergeant Melgarâs death.
Much is unknown about what happened around 5 a.m. on June 4 in the team house. The initial reports to Sergeant Melgarâs superiors in Germany said he had been injured while wrestling or grappling with the two Navy commandos, according to three officials who have been briefed on the investigation.
According to one version of events, one of the SEALs put Sergeant Melgar in a chokehold. When the sergeant passed out, the commandos frantically tried to revive him. Failing that, they rushed him to an emergency clinic, where he was pronounced dead.
Spokesmen for the Africa Command, the Special Operations Command, the Defense Department and the Army and Navy investigative services declined to comment, citing the continuing investigation, or did not respond to emails and phone calls on Sunday.
A spokesman for the State Departmentâs Africa Bureau and Mr. Folmsbee, Nicholas A. Sadoski, directed all questions to the Pentagon. Mr. Sadoski declined to answer questions about what kind of oversight the ambassador exercised over the American military personnel in Mali, how frequently he was briefed on Special Operations missions there and when he learned about Sergeant Melgarâs death.
Why American Special Operations forces are in Mali at all is a story in a nutshell of the American militaryâs successes and failures in Africa.
Mali had been one of West Africaâs most stable nations before 2012, and was held up by the Pentagon as a model partner in combating Islamic militants. But when secular Tuareg separatists began an uprising, as they had done in the past, insurgents linked to Al Qaeda took advantage of the deteriorating security situation.
When the militants surged across Maliâs northern desert in 2012, American-trained commanders of the countryâs elite army units defected at a critical time, taking troops, trucks, weapons and their newfound skills to the enemy. A confidential internal review completed by the Africa Command after the debacle concluded that there were critical gaps in the American training for Malian troops and senior officers.
With Maliâs army in collapse, the rebels were pushed out by French and Chadian troops early in 2013, and the United Nations established a peacekeeping mission. But the chaos continues today. Various armed insurgents regularly attack Malian forces and the United Nations peacekeepers. To date, 149 peacekeepers have been killed in Mali, making it one of the most dangerous peacekeeping missions in the world.
And terrorists continue to mount deadly attacks, including an assault in June on a resort outside Bamako that killed at least five people.
For the 3rd Special Forces Group, the past year has served as a reminder that Africa remains a dangerous assignment. In addition to Sergeant Melgar and the four soldiers killed in Niger, one soldier committed suicide in Kenya last October and another died in a vehicle accident while on patrol in Niger in February.
Those who knew Sergeant Melgar described him as a soldierâs soldier â he deployed to Afghanistan twice on training missions between July 2014 and February 2016, according to his Army service record â and a devoted father of two sons, 13 and 15, who texted and talked via Skype multiple times a day with his wife while serving overseas.
More than four months later, his death still has many at Fort Bragg and in Lubbock reeling. An online community bulletin board in Lubbock stated: âA Melgar family representative shared that âStaff Sgt. Melgar did what most only dream of and excelled at every turn! His life was epic! He is missed dearly every single day.ââ
Sergeant Melgar was also honored at the high school he attended in Wolfforth, Tex., Frenship High, during the homecoming football game on Oct. 6.
A final tribute awaits Sergeant Melgar: He is scheduled to be buried at Arlington National Cemetery on Nov. 20.