left the agents for dead but the wounded agent was able to call for help. law enforcement sources say questions have been raised as to why the agents stopped. how the gunmen got the into the armored vehicle. what may have been stolen from the vehicles. and if all security procedures were followed. sources believe the zeta cartel is responsible for the attack. late today secretary of homeland security janet napolitano and attorney general eric holder announced the creation of a joint task force to coordinate with mexican authorities so they can bring those responsible to justice. brian. >> jose diaz-balart from telemundo. thank you for that report tonight. when our broadcast continues on a wednesday night, the whole nation has been following her story of courage and grit. next we'll go inside the hospital where doctors show us what gabrielle giffords is doing and why it may be the hardest work of her life. and later, a star with the voice and the vision and who is giving people a shot at a better life.