A Latino father and two sons are facing serious criminal charges, including attempted capital murder, after they shot at a federal immigration agent parked outside their home along the Texas border this week.

But according to a relative, the family shot because they were afraid someone was going to break in.

U.S. Immigrations and Customs Enforcement agent Kelton Harrison was shot in the back early Tuesday, when prosecutors say Pedro Alvárez and his sons, ages 18 and 16, fired at Harrison's vehicle and chased the agent as he sped away. Prosecutors say Harrison had been watching for an anticipated drug deal. His condition is improving.

Amparo Ramírez, the family matriarch, told the San Antonio Express-News in a story published Saturday that Harrison was parked on the next-door property and that no attempt was made to notify home owners of surveillance activity.

"They thought it was somebody breaking in," Ramírez said. "The ICE didn't identify itself. The kids explained what they did."

Alvárez, 41, and his 18-year-old son, Arnoldo Alvárez, are charged with assault of a federal officer and knowingly using and carrying a firearm during a violent crime. His younger son has been charged with attempted capital murder in a state district court.

A criminal complaint alleges that the 16-year-old, whose identity is being withheld because of his age, fired about six shots from a .22 caliber rifle and that Arnoldo Alvarado fired "numerous" shots from a 9mm handgun as they rode in a vehicle being driven by their father. The vehicle had its headlights off in the pre-dawn darkness as it drove by Harrison, according to the complaint.

After being shot, Harrison was able to drive for several miles while the three allegedly followed, continuing to fire before the agent lost control of his sport utility vehicle. Other agents arrived on the scene, and one rushed Harrison to the hospital, where he underwent surgery.

Carlos Ramírez, the boys' uncle, told the newspaper that Alvárez's two sons "got scared" the night of the shooting. He said Arnoldo Alvarado spoke of going to school to be an air-conditioning technician and was planning to marry his high school sweetheart.

"They ain't bad boys, that's for sure," Ramírez said. "The only thing they did was play football."

The shooting happened near Hargill, about 25 miles northeast of the U.S.-Mexico border town of McAllen. According to the criminal complaint, Arnoldo Alvarado told authorities that his father spotted what he considered a suspicious vehicle and told him and the other teen "to get the guns."

Alvárez and his sons remain in custody pending detention hearings.

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