Photo Gallery: Building a sweat lodge

Program Note: Make sure to watch Gary Tuchman's report tonight on AC360° at 10 p.m. ET.

AC360°

An investigation into the deaths of three people who spent up to two hours inside a "sweat lodge" at an Arizona retreat has been elevated from an accidental death investigation to a homicide inquiry.

In North America, most Native American tribes use the term "sweat lodge" to refer to a dome-shaped structure where the intimate ritual of the sweat takes place.

Gary Tuchman visited a sweat lodge in Cornville, AZ, just outside of Sedona, to report on the ritual.