Southfield Capital-backed Protos Security, a provider of security guard and related solutions through its proprietary technology system and vast security vendor network, completed the acquisition of Mulligan Security, a provider of security services based in New York. Financial terms were not disclosed. "Mulligan Security is an iconic trade brand in the security services industry. This acquisition greatly accelerates the growth of our self-perform direct guard capabilities. With an impressive roster of blue-chip customers across many industries, the addition of Mulligan further diversifies Protos and makes us an attractive security services partner to customers such as real estate firms, schools, and corporate institutions. Kevin Mulligan and his talented team are a great fit with our service-first culture," Nathaniel Shaw, Protos Security CEO.