Police in the northern Mexican city of Monterrey have arrested a female assassin implicated in 20 murders for the feared Zetas drug cartel.
Maria Jimenez, 26, was paid about US$1700 per month to kill her victims, who included rival drug traffickers and a police officer, said Jorge Domene, spokesman for the state prosecutors in Nuevo Leon, Monterrey's home state.
Jimenez was arrested last week and has since confessed to the murders and other crimes, Domene said. Prosecutors will charge her with murder, car theft and kidnapping, he said.
Mexican police have arrested other female assassins but few have been suspected of so many killings.
Jimenez was detained along with three men accused of being assassins and five other men and women accused of working as drug dealers and look-outs. The group controlled 14 drug selling hotspots in Monterrey's metropolitan area, Domene said.
Once touted as Latin America's safest city, the industrial hub has been plagued by gang-related violence as the Zetas battle their rivals in the Gulf Cartel for control of drug distribution and other criminal rackets.
There have been over 50,000 drug-related killings in Mexico since President Felipe Calderon took office in December 2006 and launched a national offensive against the cartels.