Neither the Arellano Felixes nor any other drug trafficker is getting impunity

Attorney General Macedo de la Concha

Humberto Rodriguez Banuelos, alias the Frog - who had undergone cosmetic surgery on his face, had lost 40kg by liposuction and had had hair implants - was identified by a bullet wound on his right buttock.

He was arrested under a false name in April for allegedly taking part in a shootout in the border city of Tijuana.

He has now been transferred to a federal prison in the western Mexico city of Guadalajara; he is expected to face charges of homicide, drug trafficking and illegal weapons possession in Tijuana, and organised crime, homicide and kidnapping charges in Guadalajara.

He allegedly masterminded the 1983 assassination attempt against a rival drug lord and, in 1993, is said to have participated in a shootout at Guadalajara airport in which a Roman Catholic Cardinal, Juan Jesus Posadas Ocampo, was killed in crossfire.

The authorities were alerted when the false name and date and place of birth that he gave did not match official records.

The attorney general's office (PGR) said he admitted his real identity after being correctly identified by his scar in a physical examination.

He allegedly worked as the top killer for the Tijuana-based Arellano Felix cartel - Mexico's most violent criminal organisation.

The police have been criticised for not tackling traffickers

The detection was proof that police are hitting hard against all drug gangs, said Attorney General Rafael Macedo de la Concha.

"Neither the Arellano Felixes nor any other drug trafficker is getting impunity," Mr Macedo de la Concha said.

Correspondents say the recently-elected administration of President Vicente Fox has dealt a severe blow to the remnants of the Gulf cocaine cartel in raids this year.

But the top members of the Arellano Felix group, including the notoriously violent brothers, Ramon and Benjamin Arellano Felix, who control it, are still at large.

In 1997 Mexico's former anti-drug official General Jesus Gutierrez Rebollo was arrested for conducting operations against the Arellano Felixes in exchange for a pay-off from a rival cartel.