A longtime U.S. diplomat found dead last month in his apartment near the American embassy in Madagascar was identified and now, federal authorities are investigating his death as a homicide.

Newly unsealed court records unsealed show the FBI and U.S. State Department opened the investigation into the Sept. 22 death of Kevin Webb, a human resources officer assigned to the embassy in the capital of the Indian Ocean nation.

The court filings revealed that authorities arrested a guest who accompanied Webb to his apartment the night of his death.

The State Department previously declined to identify Webb or release any details surrounding his death.

Webb's guest, a "foreign national" identified in court papers as Davidasoa Randrianotahiana, entered the residential compound through the front door and provided his name and identification to a guard.

He was spotted trying to leave Webb's apartment later that night by lowering himself down from a second-floor patio, according to an application for a search warrant filed in U.S. District Court in Washington.

Once confronted, Randrianotahiana "admitted to the compound guard and a mobile patrol officer that he had fought with Mr. Webb in his apartment and that Mr. Webb had collapsed," the court filings say.

Randrianotahiana had blood on his shoes when he was taken into custody by authorities in Madagascar.

The court papers did not reveal Randrianotahiana's nationality, and it was not clear whether he had an attorney.

A team of FBI agents searched Webb's residence about a week after his death and seized a laptop computer, a rolodex, "biological samples," a piece of curtain, buttons and a memory card, among other items, according to the court filings. The search warrant authorized investigators to take "all items that may have been used as weapons to kill Kevin Webb."

Federal authorities have not released Webb's cause of death or a possible motive in his slaying. An FBI spokesman declined to comment.

A State Department spokeswoman said Webb entered the foreign service in 2003. He arrived at the American embassy in Madagascar in July 2017.

The State Department declined to say whether it has changed any security protocols at the embassy in the wake of Webb's death.