More than 200 federal agents from different departments carried out a search operation Friday in the Metropolitan Detention Center Guaynabo in suburban San Juan, the FBI office in Puerto Rico said.

The agents examined the entire prison, FBI spokesman Moises Quiñones told the media, though no reason was given for the operation.

The massive search came after the Feb. 26 murder of Lt. Osvaldo Alvaroti, an investigative officer at MDC Guaynabo, who was shot while driving home from work.

Senior officials from the Federal Bureau of Prisons oversaw the search, according to the press, which reported that cell phones, chargers, drugs and knives were seized from the inmates during the search.

Taking part in Friday's operation were agents of the FBI, Drug Enforcement Administration, the Bureau of Alcohol, Tobacco, Firearms and Explosives, and ICE Homeland Security Investigations.

The head of the FBI for Puerto Rico and the U.S. Virgin Islands, Carlos Cases, said on Feb. 28 that maximum efforts would be undertaken to get to the bottom of Alvaroti's murder.

El Nuevo Dia newspaper reported that four inmates at MDC Guaynabo, from whom Alvaroti seized several cell phones, were being investigated by federal authorities as possible suspects in the murder. EFE