She was born October 11, 1937, in Denver, Colorado. Coel is an American historian and mystery writer who now lives in Boulder, Colorado. She has written several works of nonfiction and is considered an expert on the Arapaho Indians. She created the fictional Wind RIver Reservation series of mysteries featuring Father John O'Malley and Vicky Holden. O'Malley is the Jesuit pastor of St. Francis Mission and Holden is an Arapaho lawyer who has returned to the area to help her people. There are twenty novels in the mystery series.