Defense attorneys for two men accused of killing a Special Forces soldier plan to reveal one of the agents assigned to the case started a romantic relationship with a witness.

Marine Raider Gunnery Sgt. Mario Madera-Rodriguez and Navy Special Operations Chief Anthony DeDolph face charges including murder in the strangulation death of a Green Beret, Army Staff Sgt. Logan Melgar. Both will appear Monday at a hearing in Norfolk, Virginia to determine if DeDolph and Madera-Rodriguez will face a court-martial.

Colby Vokey, Madera-Rodriguez’s attorney, said Friday that Naval Criminal Investigative Service (NCIS) agent Ethan Pickett was assigned to investigate Melgar’s 2017 death in Mali. While there, Pickett met a female witness in Mali who worked in the intelligence community and allegedly started a relationship, according to Vokey.

“Upon receipt of a credible misconduct allegation, NCIS immediately removed the agent from the investigation and referred the matter for appropriate action, consistent with applicable Human Resources guidelines and policies,” a NCIS spokesman said in a statement. “Out of respect for the ongoing investigative and judicial processes, NCIS will not comment further until those processes have concluded.”

The Navy declined to comment on the case. Pickett did not return a call or text message.

Sources familiar with the case confirmed Pickett and the witness did start a relationship, but they did not reveal what sparked it or if the relationship is still ongoing.

Vokey said the existence of the relationship taints the NCIS investigation into Melgar’s death.

“It surely raises some questions of the veracity of the investigation,” Vokey said.

But Eugene Fidell, a Yale Law School lecturer on military justice, said the alleged romantic relationship isn’t necessarily fatal to the government’s case.

“It’s early in the process,” Fidell said. “I would imagine the government will be able to repair this. It is certainly a headache and it doesn’t put NCIS in a good light.”

DeDolph and Madera-Rodriguez are the last two men charged in the death of Melgar. Two of their teammates, Marine Raider Staff Sgt. Kevin Maxwell and Chief Special Warfare Operator Adam Matthews, have already pleaded guilty in exchange for plea agreements with prosecutors.

Maxwell testified in June that when Melgar ditched the team in Mali’s capital city of Bamako on his way to a party at the French embassy, they hatched a plan to haze him. Matthews said he, along with DeDolph, Maxwell, and Madera-Rodriguez, broke into Logan’s room and taped his arms and legs. At one point, Matthews said, DeDolph applied a choke hold and Logan became unresponsive.

The SEALs tried to resuscitate Melgar with CPR and opened a hole in his throat. They then took Melgar, along with another Green Beret, to a French medical facility, where he was pronounced dead. At the clinic, DeDolph admitted to an embassy official he choked Melgar, according to NBC News and subsequent reports.

Matthews, 33, pleaded guilty to hazing and assault charges and attempts to cover up what happened to Logan and was sentenced in May to one year in military prison. Earlier this month, Maxwell, 29, was sentenced to four years of confinement after pleading guilty in connection with Logan’s death.

Monday’s hearing, called an Article 32, is like a civilian preliminary hearing mixed with a grand jury. The government will present evidence during the Article 32 that a crime was committed and the accused is responsible. Unlike a civilian grand jury, the accused is present and can present witnesses, cross-examine all government witnesses and testify. If the presiding officer finds that a crime has occurred, the case is sent back to the commanding officer who decides if the case will go to court-martial for trial.

Vokey and DeDloph's civilian attorney, Phillip Stackhouse, both expect the case to go to court martial after Monday’s hearing.