The boy -- who allegedly says he has worked for the South Pacific drug cartel since he was 11 years old -- was arrested Thursday night as he tried to board a plane in Cuernavaca, south of Mexico City. He was traveling with two of his sisters.
Known by the nickname "El Ponchis," the teen has allegedly admitted to participating in at least four decapitations, The Associated Press reported. His first name is Edgar, but AOL News is withholding his last name because he is underage.
"I participated in four executions, but I did it drugged and under threat that if I didn't, they would kill me," the teen said, according to the AP.
Drug-related violence has intensified in Mexico as cartels battle one another and the army to gain access to the multibillion-dollar U.S. market. The bloodshed has increasingly moved south from the border region to previously quiet locations such as Cuernavaca and business center Monterrey.
Edgar was born in San Diego and thus has U.S. citizenship. He was arrested as he tried to fly to the Mexican border city of Tijuana. Once there, he reportedly planned to cross the border to San Diego.
Authorities are checking to see if he is also a Mexican citizen, Reuters reported.
Rumors about the existence of a child hit man nicknamed "El Ponchis" have been circulating for weeks. He was tied to a string of murders, including beheadings.
The teen and six men allegedly confessed to killing people and hanging their bodies from bridges in Cuernavaca, Agence France-Presse reported. Cartels have taken to displaying their victims in public as a means of intimidating local authorities and the media.
Authorities say Edgar's teenage sisters were accomplices in the killings, often acting as decoys to lure victims. Some media reports even say that one of the sisters was the lover of a cartel boss. The AP quoted a source as saying that one of the sisters was accused of disposing of victims' bodies by dumping them on streets.
It is not clear what the nickname "El Ponchis" refers to.