The Johnston Group in Agoura Hills has bought an iconic six-story office building overlooking the 101 freeway in Oxnard, according to the commercial real estate company. Johnston Group, a development, property management and leasing company, bought the 115,000-square-foot building at 1000 Town Center from Equity Office Management in a deal that closed March 21, according to the company. The price wasn’t disclosed in the announcement, but sources close to the transaction said it sold for $24.2 million. The Class-A office building, with its blue-green curved glass facade, was built in 1989 and had previously housed Nordman Cormany Hair & Compton, once the largest law firm in the region, before it closed in 2013. The property was 97 percent occupied at the time of the sale, according to Johnston Group. CBRE Group Inc. Senior Vice Presidents Tom Dwyer and Michael Slater, as well as Team Shannon, represented the seller in the transaction. Johnston Group represented itself.