Meg,
The Church does not have a teaching on the exact moment when the soul leaves the body (not even doctors can agree on a solid definition of death), so She cannot answer your question.
You may, however, enjoy this experiential (not Church teaching) look at near-death experiences from a Catholic faith perspective:
Given what we've learned experientially from near-death experiences, it seems likely to me that the soul left the body on Day 1, since people who have NDEs tend to do so after a cardiac event like this.
Eric |