MCALLEN, Texas (AP) — The sister of a federal agent wounded in an attack in Mexico said Wednesday she hoped the lawsuit filed by her brother and the family of an agent who was killed will force the government to answer their questions.

U.S. Immigration and Customs Enforcement agents Jaime Zapata and Victor Avila were attacked on Feb. 15, 2011, in their armored sport-utility vehicle near San Luis Potosi, Mexico, shortly after picking up some equipment from another agent. Zapata died and Avila was seriously wounded.

The lawsuit filed Tuesday in federal court in Brownsville names nearly two-dozen defendants, among them the agents' supervisors, the company that armored their vehicle and gun shops that allegedly sold two of the weapons used in the attack. It claims Zapata and Avila never should have been sent on the dangerous mission, their armored SUV was flawed and at least two of the guns used in the attack were bought in the United States and eventually smuggled to Mexico.