Updated

A recent spate of fatal shootings along the U.S-Mexico border has renewed outcry over the U.S. Border Patrol's use-of-force policies and angered those who believe it is a disturbing trend.

In the latest case, a 16-year-old boy was fatally shot in October in Mexico by an agent standing on the U.S. side of the fence that separates the two countries in Nogales, Ariz. The agent claims the boy was throwing rocks, and Border Patrol policy allows the use of lethal force in such cases.

But critics say such tactics are excessive and brutal.

They say at least 16 people have been killed by agents along the border since 2010, eight in instances where federal authorities said they were being attacked by rocks.

The Border Patrol has declined to comment.