Wow! I was not aware that the rules were that specific. Thanks again.
The canons are given in the article:
Canon 1090 §1 of the 1983 Code of Canon Law is clear: One who, with a view to entering marriage with a particular person, has killed that persons spouse, or his or her own spouse, invalidly attempts this marriage.
Canon 1090's second paragraph is similarly clear: They also invalidly attempt marriage with each other who, by mutual physical or moral action, brought about the death of eithers spouse. Thus canon 1090 defines what canonists call the marriage impediment of crime (or crimen).
When you've been around for a few millennia, you tend to cover all the bases. If death dissolves the marriage bond, how long do you think it took someone to figure out he could kill his wife to marry a new one? Not very long, I bet.
SD