Hundreds of employees of Commonwealth Financial, the country’s fourth-largest independent broker-dealer, were directed to head to the firm’s emergency backup office outside of Boston Friday morning as law enforcement officials announced a citywide lockdown.

“The first email went out to managers at 6:32 a.m. and the staff at 6:48 a.m. alerting everyone who is to go to the second office,” Commonwealth founder and Chairman Joseph Deitch said in an interview. “I would assume that 90% of our people will either be able to be up and running in their homes or in our backup office,” which can accommodate 200 people, he added.

Police and federal officials told workers and residents to remain in their homes Friday morning, according to news reports, while they hunted for suspects in the bomb attack at the finish line of the Boston Marathon on Monday that killed three bystanders and injured 175 people. The manhunt became a widely televised firefight in Watertown, Mass., early Friday; Watertown is just a few miles from Waltham, where Commonwealth is based.

A bit more than 500 people work in the firm’s headquarters, Deitch said. The company’s 1,500 advisors nationwide will remain able to serve their hundreds of thousands of clients through the Boston crisis in a variety of ways, he said. Many will work from home. Many will be backed up by about 100 Commonwealth employees in the firm’s San Diego offices.

But those who are able to leave their homes to work in Commonwealth’s backup office space will find computers and phones. The space sits empty almost year-round, Deitch said, awaiting emergencies like the one Commonwealth is now encountering.

“It’s way, way out of the city and off the grid,” he said. “Years ago, we decided to get a dedicated space. It’s very unglamorous.”

For years, the firm contracted with a company that guaranteed it access to offices in case of an emergency, according to Deitch. However, Commonwealth officials concluded that in case of a widespread emergency, the offices might not be available. That lead to the decision to obtain permanent and dedicated backup space – which had not yet been used, Deitch said. “When you start your business, you are looking to stay alive and grow,” he said. “You hope it grows and become a success. Then, one day you realize, ‘Hey, we need to protect our flanks.’”

Deitch, who spends four months a year working in Massachussetts and the other eight in Florida, was in the South when news broke of the manhunt yesterday. He says he stayed up until 1 a.m. following the news, knowing he could sleep through the night and leave any decision-making to his firm’s risk management department. “About 15 years ago we started a risk management department and began discussing literally anything and everything that could go wrong,” he said.

Deitch said “many, many people” in his firm and social circle have been affected by the events of the week.

One Commonwealth worker was volunteering at the marathon on Monday morning, he said, when a friend asked her to accompany her to get a sandwich. She said no, Deitch said. The woman declined and the friend asked again – and then again, he said. Finally the friend said, “I just want you to keep me company” and she relented, he said. Had she remained at the marathon, she would have been right near the second bomb.

On Friday morning, Deitch said he “ran and put the TV on the second I was awakened by a text” from his firm’s risk management department.

Staffers of the Colony Group, a Boston RIA firm that has about 60 employees, also were told to stay home Friday amid the manhunt.

“At about 7 a.m. I sent an email to employees that there was a lockdown -- asking everyone to work from home,” said Michael Nathanson, Colony’s CEO. Like so many people across Boston and around the world, “We're grieving,” he added. “We have been pleasantly overwhelmed with the outpouring of support from across the country. We’ve heard from clients around the country – it’s nice to get that outpouring of support and sense of community in the industry.” 

With Paula Vasan