Holgate has been a teacher at the school for over 20 years, and Battillo volunteered in her class. Battillo also served as the head coach of the boys basketball team.
Prosecutors say the couple justified the three killings with doomsday beliefs, part of an elaborate scheme to eliminate any obstacles to their relationship and to obtain money from survivor benefits and life insurance.
Phoenix Police Interim Chief Michael Sullivan announced last week Mower was one of three suspects arrested in the March 30 shooting near 33rd and Southern avenues.