A large article in today's
The Arizona Republic indicates that the only brass found was from their caliber weapons, Ivie was alone, the other two (male and female) were together. They approached from different angles, and someone - the story said Ivie (but he's not around to defend himself) - got nervous and fired, and the others returned fire. It was 0130 and very dark in a very brushy area.
http://www.azcentral.com/arizonarepu...ndly-fire.html
Sad...anyway you slice it.