members of MS-13, well-known for being ruthless, are coming to Arizona because its position on the border makes it a hot spot for drugs

``Murdering someone is not a concern to them, it's a cost of doing business almost," Scioli said. ``Just their initiation to get into the gang is pretty aggressive." One of the fastest-growing and most violent gangs in the world is showing up in Arizona. Mike Scioli with the Border Patrol said members of MS-13, well-known for being ruthless, are coming to Arizona because its position on the border makes it a hot spot for drugs and human smuggling. MS-13 comes from El Salvador and has an estimated 100,000 members throughout Latin America and the United States. Many of the gang's founding members had experience or training in guerilla warefare in El Salvador. It's one of the fast-growing gangs in the world. Scioli said the presence of MS-13 gang members is making federal agents along the U.S.-Mexico border nervous. ``It's not uncommon for a single agent to run into a group of 10 to 13 people and make the arrest alone, on his own, with backup maybe a half-hour away," he said. Many of the gang's founders are highly-trained rebel fighters from El Salvador, he added.