Ex-internal affairs chief criticizes Border Patrol training

The former head of internal affairs at U.S. Customs and Border Protection says in a Supreme Court filing that an agent who killed a Mexican teen in a cross-border shooting should be held accountable.

James Tomsheck said in a brief submitted Friday that poor screening and inadequate training has resulted in an environment in which Border Patrol agents use unnecessary lethal force on the U.S.-Mexico border.

Tomsheck was the assistant commissioner of the CBP Office of Internal Affairs from June 2006 to June 2014, overseeing use-of-force investigations.

The brief was filed in the Supreme Court case involving an agent who fatally shot 15-year-old Sergio Adrián Hernández Guereca in 2010. A lower court ruled that the boy's family couldn't sue because he was in Mexico at the time of the shooting and wasn't constitutionally protected.

Sergio Adrían is one of six victims killed in Mexico by a Border Patrol agent in recent years.