Gunmen dressed as clowns have shot dead one of Mexico’s most powerful former drug lords while he was attending a children’s party.

Francisco Rafael Arellano Felix, 63, was at the party during family celebrations in Cabo San Lucas, a major tourist resort in the Baja California peninsula of Mexico, AP reports.

Gunmen dressed in costumes which included a wig and a round red nose entered the party which was being held in the luxurious Casa Oceano tourist area.

Arellano Felix was hit at point blank range “by two bullets, one in the thorax and one in the head,” state special investigations prosecutor Isai Arias told AP.

The “clowns” then fled the crime scene and a massive police operation failed to find them.

Farncisco Rafael was the oldest of seven Arellano Felix brothers, who once dominated drug trafficking between Mexico and California through their brutal cartel, inspiring characters in the Steven Soderbergh film, “Traffic.”

The Tijuana cartel was one of Mexico’s three largest drug outfits, but most of the brothers have been either killed or arrested, leaving rival groups to take over the trade.

The cartel made headlines in 2006, when it was discovered they had dug trafficking tunnels from Tijuana through to California.

Francisco Rafael Arellano Felix was arrested in 1980 in San Diego, California, for selling drugs and returned to Mexico upon his release on bail.

In 1993, he was arrested in Mexico and jailed on drug charges.

He was extradited to the United States in 2006 and was sentenced to six years in prison after confessing to selling drugs to an undercover agent.

He was released in 2008, winning time off his sentence for good behavior, and repatriated to Mexico, according to his attorney at the time.

Police killed another brother, Ramon, in a shootout in 2002.

Three other brothers are in US prisons, including Eduardo, who was sentenced to 15 years by a California court in August for money laundering.

Security experts believe the cartel is now run by the brothers’ sister Enedina and her son Fernando, known as “The Engineer.”

Violence linked to drug trafficking and organized crime has left more than 70,000 dead in Mexico over the past seven years.

This story originally appeared on News.com.au.