A federal appeals court on Monday overturned the convictions of three former Probation Department officials, ruling that the government “overstepped its bounds in using federal criminal statutes to police the hiring practices of these Massachusetts state officials.” Former Probation Commissioner John O’Brien and former deputy commissioners Elizabeth Tavares and William Burke were convicted in 2014 for their roles in a patronage scheme in which they “abused the hiring process… in exchange for favorable budget treatment from the state Legislature and increased control over the Probation Department,” three U.S. Court of Appeals for the First Circuit judges wrote in their opinion.