Developer Ken Mattson has sold at least a dozen properties in and around Sonoma this month. But, it’s unclear who the buyer or buyers are. The properties sold in the past month include the Sonoma Cheese Factory building on the town plaza and Sonoma’s Best deli, where Mattson has an office. Between 2015 and 2023, Mattson bought all of or part of 116 properties in and near Sonoma.