Pensacola, Fla. ? An ex-convict who taught self-defense to children. A day laborer who served prison time for killing a man in a fight. An Air Force staff sergeant attached to an elite special operations unit.

Somehow, authorities say, they ended up part of a loosely connected group of seven men charged in the shooting deaths of Byrd and Melanie Billings, a wealthy Florida Panhandle couple known for adopting children with special needs.

The suspects, some dressed as ninjas, stole a safe and other items during the break-in Thursday at the sprawling Billings home west of Pensacola. Nine of the couple’s 13 adopted children were home at the time. Three saw the intruders but were not hurt. Authorities would not say what was in the safe or what else was taken.

Some of the masked men entered through the front door, while others slipped in through an unlocked utility door in the back. They were in and out in under 10 minutes. The crime was captured by an extensive video surveillance system the Billings used to keep tabs on their many children.

“It was a very well-planned and well-executed operation,” said Escambia County Sheriff David Morgan.

The last three of the seven suspects were arrested Tuesday, though Morgan said there still might be more arrests.