TUCSON, Ariz. (CN) - A Border Patrol agent shot and killed a teenage U.S. citizen in the back as the young man fled from a traffic stop near the Mexican border, his mother claims in a federal lawsuit. Carlos LaMadrid died at a hospital after being shot three times by the unknown agent on March 21, 2011, his mother, Guadalupe Guerrero, says. She claims Border Patrol officials gave bad directions to the ambulance carrying her son, delaying medical care. ”At the time of the shooting, Mr. LaMadrid was completely defenseless,” the complaint states. “Mr. LaMadrid was in the process of fleeing and climbing a ladder over a fence and had his back turned to the agent. Mr. LaMadrid had no weapon of any kind on or near his person, and he was not threatening the agent or any third party. The shooting was clearly in violation of Mr. LaMadrid’s rights under the United States constitution.” The incident began when Douglas police officers got an anonymous tip that a Chevrolet Avalanche, in which LaMadrid, 19, and Jesus Manuel Chino Lino, 17, were riding, was transporting marijuana, according to the complaint. Douglas is a border town about a 2-hour drive southeast of Tucson. ”Officers with the Douglas Police Department reportedly spotted the alleged Avalanche and began pursuing the vehicle,” the complaint states. “The Avalanche refused to pull over and instead made its way to the border fence separating the Republic of Mexico from the United States.” The Avalanche stopped at the border fence and LaMadrid jumped out as Border Patrol agents arrived. ”Upon information and belief, the agent and unknown Border Patrol agents had no knowledge of why the Douglas Police Department was in pursuit of the Avalanche or the circumstances which gave rise to the pursuit,” LaMadrid’s mother says. Her son ran to a ladder propped against the border fence, but could not get over before the agent shot him at least three times in the back, Guerrero says. ”The agent then drew his sidearm and took aim at Mr. LaMadrid who was in the process of climbing the ladder,” the complaint states. ”In an appalling use of excessive force, the agent intentionally fired at least three shots at Mr. LaMadrid.” Guerrero says that agents handcuffed her son’s hands and feet, dragged him to the back of the patrol vehicle and called for an ambulance. ”The ambulance, however, was initially sent to the wrong location thereby delaying its arrival,” Guerrero claims. “Prior to the ambulance’s arrival, law enforcement provided inadequate first aide to Mr. LaMadrid despite the obvious gunshot wounds that Mr. LaMadrid had sustained.” With two bullets in his back and one in his thigh, LaMadrid died a short time later at the hospital, Guerrero says. She claims her son’s death was part of pattern of unchecked and unreported violence by the Border Patrol. ”Ms. Guerrero alleges, upon information and belief, that a significantly higher number of shootings have in fact occurred along the international border between the United States and Mexico, however, many of these shootings and other acts of physical and verbal abuse of Mexican citizens and United States citizens of Mexican descent have gone unreported by United States Border Patrol agents,” the complaint states. “The United States Border Patrol had reason to know of the significant number of unreported incidents and have failed to investigate the information concerning abuses of their agents.” Guerrero seeks exemplary damages for violations of her son’s civil rights.