During the penalty phase of the trial, Bundy took advantage of an obscure Florida law
providing that a marriage declaration in court in the presence of a judge constituted a legal marriage. As he
was questioning former Washington State DES coworker Carole Ann Boone—who had moved to Florida to be near
Bundy, had testified on his behalf during both trials, and was again testifying on his behalf as a character
witness—he asked her to marry him. She accepted, and Bundy declared to the court that they were legally
married.

http://www.trutv.com/library/crime/serial_killers/notorious/bundy/18.html