Mexican cartel violence spills into U.S. as 'drug assassin' pleads no contest to beheading man in Arizona

• Crisantos Moroyoqui-Yocupicio, 39, has pleaded no contest to 2010 beheading in Phoenix apartment
• Only one of three suspected hit men have been arrested
• Cartel killings in U.S. are said to be rare out of fear of attention from American authorities
• Victim and four suspects all are from Mexico and were in the U.S. illegally

A Mexican man has pleaded no contest to beheading a man in Arizona who police say stole drugs from the El Chapo drug trafficking organization launching the grisly attack authorities fear to be spreading across the U.S. border.

Crisantos Moroyoqui-Yocupicio, 39, entered his plea on Monday to second-degree murder in the death of Martin Alejandro Cota-Monroy, 38, who was killed at a Phoenix apartment in 2010 after allegedly tracked by three hit men sent from Mexico.

Police believe Cota-Monroy's gruesome killing was intended to send a message that anyone who betrays the traffickers will get the same treatment.