The story is that Pope Paul read through the letter in silence then suddenly exclaimed, "Ah, Agatha Christie!" and then signed it. Though not a Catholic at the time, Christie rejected the 20th century rite as the desecration of the historic church that it was. The indult was granted in 1971. Ever since it has been known informally as "the Agatha Christie indult".
Sacra Congregatio pro Cultu Divino
E Civitate Vaticana,
die 5 Novembre 1971