The review of U.S. Customs and Border Protection enforcement practices followed a request by 16 congressional members who said they were concerned about the death of a Mexican man who suffered a fatal heart attack after a customs officer used a stun gun on him in 2010, the Los Angeles Times reported Wednesday.
The Homeland Security's Office of Inspector General's review will determine whether the incident was indicative of systemic brutality or use of excessive force, and whether staff increases in recent years affected training, officials said.
Since 2010, agents have killed at least 16 civilians, many during rock-throwing confrontations involving suspected smugglers, the Times said
The department's guidelines state agents may use lethal force in such situations because rocks and other thrown items have caused serious injuries. Investigations have cleared most agents of wrongdoing.
"CBP law enforcement personnel are trained to use deadly force in circumstances that pose a threat to their lives, the lives of their fellow law enforcement partners and innocent third parties," U.S. Customs and Border Protection recently said in a statement.
Human rights advocates and civil rights groups praised the decision to review the guidelines.
"Knowingly hiring bad apples, having a policy of shooting first and asking questions later, being accountable to no one, all point to an agency that is out of control," Christian Ramirez, human rights director for the immigrant advocacy group Southern Border Communities Coalition, told the Times.
In their letter, lawmakers urged the department's inspector general to determine whether the stun-gun incident is "emblematic of a broader cultural problem within CBP," as well as questioned whether other fatalities were fully investigated.
"There are serious problems raised by this series of deaths tied to the department, and the fact that there did not appear to be an effort by the department to fully investigate the incidents," the letter said.
A congressional employee said the Department of Homeland Security report likely won't be completed until next year.
Notable deaths of 2014 [PHOTOS]