Francisco Rafael Arellano Felix, 63, the eldest brother of Mexico’s once-feared Arellano Felix drug clan, was shot to death in the Baja beach resort of Los Cabos by a gunman wearing a clown costume, authorities said Saturday.

Relatives of Arellano Felix confirmed his identity at the scene of the crime at a rented beach house, the attorney general’s office in Baja California Sur state said in a statement.

A photo from the scene showed his body sprawled on the tiled floor of the open-sided, beachfront house, covered by a sheet.

An official of the Baja California Sur state prosecutor’s office said Saturday that the killer wore a clown costume complete with a wig and a round red nose. The official was not authorized to be quoted by name.

The motive for the attack, and the gunman’s disguise, are still under investigation.

Known for its violent and brutal control of the drug trade in the border city of Tijuana in the 1990s, the arrests or death of most of the seven Arellano Felix brothers have reduced the cartel to a shadow of its former self.

Arellano Felix was already in prison when the gang rose to its height.

“He was never really part of the leadership of the big organization, mostly because he was in jail (in Mexico). He was arrested before they became what they really became,” said John Kirby, a former federal prosecutor in San Diego who co-wrote a 2003 indictment against the Arellano Felix cartel leadership.

Arellano Felix was arrested in 1993 in connection with the murder of Roman Catholic Cardinal Juan Jesus Posadas Ocampo and served a 10-year sentence for weapons possession. Mexican officials were concerned that he would return to drug trafficking after serving his Mexican sentence and asked their U.S. counterparts to seek his extradition as he neared completion of a sentence on the unrelated weapons charge.

“The Mexicans were very concerned he was going to get out,” Kirby said.

Kirby said he found enough evidence to bring charges on the 1980 drug case and he prepared the extradition request.

Arellano Felix was extradited to the U.S. in 2006 to face California charges stemming from a 1980 case in which he allegedly sold cocaine to an undercover police officer in the United States.

He was sentenced by a U.S. judge to six years in prison on drug charges but was granted parole, released and deported to Mexico in 2008.