Cardinal Sean O'Malley announced Thursday he is expanding the review to meet "the generally expected levels of transparency and accountability."
The investigation began in August when two former seminarians at St. John's Seminary in Brighton posted accounts on social media of witnessing and experiencing activities "directly contrary to the moral standards and requirements of formation for the Catholic priesthood."
That investigation now covers Pope St. John XXIII National Seminary in Weston and Redemptoris Mater Seminary in Brookline.
Former U.S. Attorney Donald Stern will lead the investigation.
O'Malley is Pope Francis' top adviser on sex abuse. Boston was the epicenter of the priest abuse scandal.
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