Lawsuit: "Trigger-Happy" Cop Shot Grandpa

Allegations by the family of a man shot in Scottsdale, Arizona while holding his infant grandson

An unarmed man carrying his infant grandson was shot in the head by a cop with a known "propensity for killing civilians," his family says in federal court.

Scottsdale police had allegedly arrived at the home of John Loxas Jr. on Feb. 14, 2012, after the 50-year-old had argued with a neighbor.