Police discovered the body of the First Secretary of the Libyan embassy in the Spanish capital on Friday.
Faucina M.A. was found at home by her daughter, reported news agency EFE on Tuesday.
Police say there were clear signs of violence on her body, including a heavy blow to the head and numerous bruises.
Although they are still investigating the death of the 58-year-old diplomat, evidence suggests the woman possibly suffocated.
The Libyan embassy was unavailable for comment.