MEXICO CITY — The leaders of clowns gathered for a convention in Mexico City said Wednesday they are saddened that a killer disguised himself as a clown to kill a drug lord last week, and insisted no true member of their profession would have committed the crime.

Convicted drug trafficker Francisco Rafael Arellano Felix was shot to death Friday in the Baja beach resort of Los Cabos by a gunman wearing a clown costume, including a wig and a rubber nose. The dead man was the eldest brother of Mexico’s once-feared Arellano Felix clan.

Clown leader Tomas Morales, a 21-year veteran of the trade who goes by the stage name “Payaso Llantom,” said he was certain the killer was not a professional clown.

He said clowns in Mexico, especially in outlying states, know each other and their costumes and makeup are individualized and recognizable.

“The people who do that, they’re not clowns. I can swear on my mother’s grave it wasn’t a clown,” said Morales.

“We are not like that … we are nonviolent.”