Dunn and Womack lead a 24-member private security team employed by their Roxbury nonprofit, the Nubian Square Foundation, which has been staffing the shelter since it opened last month. Under a subcontract with the provider running the shelter, the state pays them $20,000 a week to provide three shifts of around-the-clock security services for the families inside, while working the perimeter to keep protesters or bad actors at bay. Pausing for a moment, Dunn, a tall man with a white beard, puffed his cheeks out at a toddler, who responded with a giggle. Will Dunn and Chris Womack walked the...