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, plus another arrest announced Monday evening, but the mystery around town only deepened, 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.
"Mr. Billings was well-to-do. He was an entrepreneur and he opened his home to the community. You are asking me to speculate on a motive. That could have been one reason," Morgan said, likening the killings to the 1959 slayings of a Kansas farm family that were chronicled by Truman Capote in the book "In Cold Blood."
The video from last Thursday showed three armed, masked men arriving in a red van, entering through the front of the house and then returning to the vehicle. Others dressed in what the sheriff called "ninja garb" went in through an unlocked utility door in the back. They were in and out in under 10 minutes.
The sheriff would not say what, if anything, was stolen.
Some of the nine children in the house at the time were sleeping, but several others saw the break-in, authorities said. One left the house and went to get a neighbor, who called 911.
"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.
The Billingses owned several local businesses, including a finance company and a used-car dealership. They lived in Beulah, a rural area west of Pensacola, near the Alabama state line, in a house set deep in the woods. They had 16 children in all - 12 of them adopted.
In a 2005 story in the Pensacola News Journal, the couple said they wanted to share their wealth with children in need, but didn't imagine their family would grow so large.
"It just happened," said Melanie Billings, who was 43 when she died. "I just wanted to give them a better life."
The surveillance system was installed to help the couple keep track of their children as they wandered through the large house and yard, said Susan Berry, principal of Escambia Westgate School in Pensacola, which some of the children attended.
Tips from the public led police to the van on Saturday. Day laborer Wayne Coldiron, 41, turned himself in on Sunday, and Leonard P. Gonzalez Jr., 35, was arrested the same day in a neighboring county. They were charged with murder and home invasion. Gary Lamont Sumner Jr., 30, was arrested Monday in Okaloosa County on a murder charge and will eventually be returned to Escambia County. Morgan said he hopes to make another arrest on Tuesday.
Authorities also jailed Gonzalez's father on a charge of evidence tampering. Police say the 56-year-old confessed to driving a getaway van and trying to repaint it later, reports CBS News correspondent Mark Strassmann.
The elder Gonzalez told investigators that he was the getaway driver and waited in the van while the others broke into the house and burglarized it, according to court papers. Authorities said he also told them several other men were involved.
Byrd Billings, 68, was a man with big twinkly-eyed smile, Berry said. At one school function, his big hand enveloped hers, leaving a neatly folded check for the school in her palm. She wouldn't say how much the check was for, but she couldn't believe how big it was.
"They weren't only generous with their children," Berry said. "They were generous with everyone that touched their children's lives."
When Melanie Billings picked up her children from school, she would stretch out her arms, and "the kids would run to her, the ones that could," Berry said. "They would go as fast they could with their arms in the air for Mom to take them."
For one daughter's prom, the couple created a Cinderella scene. The girl's dress was white, her date wore a white tuxedo with a pink tie, and the couple emerged from a white limousine.
"The beam on Byrd and Mel's faces, and on the parents of the young man, is something I'll never forget," Berry said. "It was picture-perfect."
Ashley Markham, an adult daughter of the victims, said she plans to carry on with her parents' legacy.
"My mother always told me some people grow up wanting to be doctors or lawyers or teachers. She wanted to be a mommy," Markham said in a statement. "Her lifelong dream was loving her babies and being a voice for them."
A funeral service has been planned for Friday morning at the Liberty Church, with visitation planned for the night before.