"This is a very difficult time for us. We ask the media to respect our privacy," they say in a statement handed to reporters camped outside the family home in Arizona.
"There are no words that can possibly express how we feel. We wish there were, so we could make you feel better. We don't understand why this happened. It may not make any difference, but we wish that we could change the heinous events of Saturday.
"We care very deeply about the victims and their families. We are so very sorry for their loss."