From an October 6 Facebook post from Andrew Schaeffer:

Sad to learn of the death of Roger Petrich this morning. Though he spent most of his career in the Roman Catholic tradition, Roger served as the Director of Music at Luther Memorial in Madison, Wisconsin from 1970-1978. While at Luther Memorial, he was instrumental in shaping the publication of the Lutheran Book of Worship. Along with Mark Bangert, Roger was primarily responsible for the psalms, and composed some of the simple tones many of us still use to this day, in addition to some other liturgical music scattered throughout the book.
Roger was a prolific composer having studied privately with Leo Sowerby and Ernst Pepping. Some of his compositions are still available through Oxford University Press, Selah, and MorningStar. When he died he was working on a new musical setting of Holy Communion for the upcoming centennial of Luther Memorial’s building. I hope to be able to share it with all of you once I get permission! Rest in peace, dear Roger.