LAREDO—At the same time that Mexican cartels appear to be gearing up for war, Homeland Security officials are making a public plea for information on suspicious cross-border activity. “Obviously, arms going to Mexico is a big part of that—that building up between the cartels,” said Timothy Tubbs, acting special agent in charge of Homeland Security investigations (HSI) in San Antonio. HSI is the investigative arm of Immigration and Customs Enforcement (ICE) and is responsible for investigating transnational crime and threats. “We’re hoping by stopping these weapons going to Mexico we can not only reduce the violence in Mexico, but allow the government of Mexico to do their job in combating the cartels,” Tubbs said at a press conference in Laredo on July 2. “By reducing the violence in Mexico, we will also keep the violence from crossing over to the U.S. and keep that from rising up in the U.S.” …