Criminal Minds (2005) - 1x16 - The Tribe

The BAU team investigates the mass murder of five college students killed in a method similar to that used by a local Native American tribe in times of war long ago.

Gideon, Hotchner and their team believe that a pack of killers who are part of a dangerous cult may be responsible for the student deaths. They interview the residents of a nearby Indian reservation, as well as citizens of the surrounding community, in an attempt to track down the killers. Meanwhile, Hotchner's handsome younger brother pays him a surprise visit at the Behavioral Analysis Unit headquarters.