PENSACOLA, Fla. – Byrd and Melanie Billings had a growing brood of adopted children with autism, Down syndrome and other disabilities, and took care to make their nine-bedroom house a safe place for them, wiring it with surveillance cameras in every room.

It was those cameras that captured images of the masked men who shot the wealthy couple to death in a break-in executed with chilling precision.Authorities made three arrests over the weekend, but the mystery around town only deepened Monday, when Sheriff David Morgan said that as many as eight people in all may have been involved and that the crime appeared to have “numerous motives,” though robbery was the only one he would mention.”I think you’ll find this particularly chilling and here’s why: We have a team that enters at the rear of the home and another that enters at the front of the home,” Morgan said. “It leads me to believe this was a very well-planned and methodical operation.”Morgan said, however, that there was no indication anyone had unlocked the door for the intruders, explaining, “I believe it was a matter of course in this community that they felt comfortable enough to leave the door unlocked.” He also said he knew of no connection between the men under arrest and the Billings family.