I notice that the article didn't mention how he got across the border. He either had to float across the Rio Grande or use a Mexican visa or shopping card. My guess is that he had a Mexican visa or a fake American dirvers license.
He evidently had enough money to purchase a car.
Another interesting report in today's OC Register is titled Nations gang up to stop gangs. Lead says: "El Salvador, Guatemala, Honduras and the U.S. seek ways to work on crime fight."
An AP article by Traci Carl datelined Apopa, El Salvador, has the FBI, Homeland Security and So. Cal. law enforcement there with gang members rounded up by Salvadoran police. About 50 officals from the nations were taking part in a 3-day conference that included talking to reformed gang members, visiting jails and interviewing those rounded up in the pre-dawn raid. The article also mentions the arrest of Rivera Paz.