The mother of a 19-year-old man fatally shot in the back by a U.S. Border Patrol agent has sued the federal government and the agent himself, claiming it was "an appalling use of excessive force" because her son was unarmed, had his back to the agent and posed no threat.

A pregnant, unarmed woman was shot during a drug raid in Spokane, Washington on Friday morning, and she remained hospitalized as investigators pieced together exactly what happened in the county's third officer-involved shooting within a month.