John T. McNeil, an assistant US attorney who prosecuted several corrupt politicians and police officers, has been named the top assistant to the US attorney for Massachusetts, Carmen M. Ortiz. McNeil takes over as first assistant US attorney, succeeding Jack Pirozzolo, who served in that role for more than four years and recently left for the private sector. McNeil has served with Ortiz as deputy chief of the criminal division, acting chief of the major crimes unit, and counsel to the US attorney. He was the lead prosecutor in several high-profile cases, including the convictions of former state senator Dianne Wilkerson, former city councilor Chuck Turner, and former Massachusetts House speaker Thomas Finneran. McNeil also initiated the first federal investigation of clergy sexual abuse and reached the first criminal settlement in the United States with a Roman Catholic diocese, the Archdiocese of Boston.