(AP Photo)
(AP Photo)

The family of slain Border Patrol Agent Brian Terry continues to push for answers on the failed U.S.-Mexico gun walking operation that led to his death.

FOX's William LaJeunesse reports:

Three years after border patrol agentĀ Brian Terry died, the family still has questions. Terry cousin Robert Heier:

Heier: "We know who in ATF and U.S. Attorneys office were found negligent in putting this operation into place, but we still don't know why."

Terry's death prompted ATF Agent John Dodson to blow the whistle on operation 'Fast & Furious'-- a government approved plan that allowed thousands of guns into Mexico where they killed countless innocent victims. Congress is also searching for answers. The House sued to obtain what it believes are incriminating documents that show who knew what about the operation.

The Terry family is appealing a ruling that it cannot sue the Federal government.

In Los Angeles, William LaJeunesse, FOX News Radio.

Click HERE to read more about operation 'Fast & Furious'