It was a brazen heist: A housekeeper was led around a seaside mansion at gunpoint as a thief made off with precious valuables, and then was tied up in the garage as the suspect made off in a stolen Porsche.
Fittingly, the investigation into the high-profile case, which police this week said is intensifying, has played out like a detective novel.
From the outset, experts — even the home’s owner — have said that the violent theft had the hallmarks of an inside job, and that the person who pulled it off was likely familiar with the house and where its high-value items were stored.
So how many people would have been familiar with a home as grand as this one, a 17-room estate perched on a cliff, with a broad lawn and a private beach?
Quite a few, say experts in household staffing for the ultra-wealthy, who manage the unseen employees who keep the region’s largest homes running from one season to the next.
“It really depends on the size of the home. You could have a staff of one, or you could have a staff of 15 or 20,” said Sarah Washburn, owner and founder of The Washburn Agency, based in Boston. “I think people that are buying a home of that size, they’re buying it knowing it will be staffed. It’s just too much. One person just physically can’t do it.”
Up the gated driveways and behind the double doors in Prides Crossing, the tony coastal neighborhood in Beverly where the burglarized property sits, a small army of staffers and vendors of all kinds might be needed, the experts said.
So police set on interviewing everyone who had worked in a home like this would have their work cut out for them.
Police said that the investigation is advancing but did not elaborate. And though authorities have not disclosed what was taken, the homeowner, investment banker Thomas J. Swan III, described it as family valuables.
Large homes can function like small businesses, industry leaders said. For the wealthiest homeowners, staff might include nannies, cleaners, a groundskeeper, security personnel, and a chef (or several, working in shifts). Plus, for some, a house manager, estate manager, and director of residence (all separate roles with distinct jobs) to oversee them and handle payroll. Then, add in a churn of vendors for home repairs, sound system installation, or pool maintenance who come by periodically, depending on the owner’s needs. And then, the tennis courts. Or horse stables.
Homeowners have been getting more sophisticated with their safety tools and protocols in the past decade, as home security technology has gotten cheaper and better, and amid heightened anxiety about being prepared for any and all threats, said Sara Cassinelli, owner of Boston-based household staffing agency Cass & Company.
“It used to be that if we have a gate and a home-alarm system, we’re OK. That’s not the case anymore. As people’s lives become more public, clients have greater visibility. Wealth at the high end has grown,” she said. “Mindfulness around security has increased exponentially, and so have the resources.”
Contracts with employees have changed, too, with new privacy and security provisions. It’s been standard in the industry for staff to sign nondisclosure agreements, undergo background and credit checks, and take drug tests. Now they can also be asked to sign contracts that specifically forbid posting to social media, to keep people from sharing too many details about their employer’s opulent lifestyle.
Much of the day-to-day management of a house with a staff can now be done remotely. Steven Rysz, an estate manager on Martha’s Vineyard, said he oversees seven properties, tracking the movements of everyone who comes and goes from the homes.
“It’s the little details,” said Rysz, who has 30 years of experience in the industry. “Tracking the principals, knowing where the kids are at all times, knowing the schedule, what time the housekeepers come.”
He runs a tight ship, he said.
The license plate of every car that visits is tracked. Everyone who crosses the threshold signs a nondisclosure agreement. Rysz pays to conceal the tail numbers on private jets and seals the records to building plans for his clients’ homes. “Because guess what that tells you? The bedrooms, the windows, the bathrooms.”
He insists that his clients not have garage door openers. Too risky, he said. “It’s like leaving the keys to your house on the dash.”
As for the people who work in a house irregularly, he said he prefers to work with trusted vendors, and no one else.
“I want to deal with the same technician every time,” Rysz said. “I don’t want the new kid who just started at the house telling his friends, ‘Oh, my God. You should have seen the piece of artwork.’ ”
There are other ways around the problem of too many strangers in the house for people who don’t want to, or can’t, maintain a large home on their own.
Among the services offered by Monarch Luxury, a property management and lifestyle concierge based in Connecticut, is an “owner’s rep,” who doesn’t live on the property, but is on call when needed to supervise anyone who comes by to fix a leaky faucet or wash the windows.
“We make sure we’re present to oversee any sort of maintenance, any sort of entry by vendors, to make sure that they are doing their job. They’re not wandering the house and casing it,” said Carol Caprio, the company’s vice president.
One of the issues her clients worry about is turnover, she said. They worry that in a few years’ time they may cycle through lots of employees, and that an untold number of people might know when the owners are away, where their security cameras point, and the contents of their Rolex collection.
“Our clients don’t trust a lot of people,” Caprio said. “They really don’t want someone knowing where their valuables are.”
Emily Sweeney and Lea Skene of the Globe staff contributed to this report.
Spencer Buell can be reached at spencer.buell@globe.com. Follow him @SpencerBuell.