The biggest riddle is what could possess Montgomery to kill, especially given his background as a peace activist and social worker. Montgomery, who was raised in King of Prussia, Pa., a suburb of Philadelphia, graduated from the University of Dayton in 1988 with a bachelor's degree in social work. While there, he was a member of Ploughshares, a national peace-activists group that has roots in his Pennsylvania hometown. After undergraduate school, he earned a master's degree in social work from Catholic University in Washington, D.C. In the early 1990s, he moved to New York, where he worked with Brooklyn Catholic Charities and as a social worker with a hospital, helping place children in foster homes and with adoptive parents. In the mid-1990s, he entered the Franciscan order, studying in Michigan and Indiana before enrolling at the Catholic Theological Union, a graduate school in Chicago.