The Murder of Laci Peterson

On December 6, Shawn Sibley heard through a business contact that Peterson was married. Peterson had told the man that he'd sold his European company and moved to California to found Tradecorp; he said he and his wife had liked Modesto so much that they bought a house right away. Sibley confronted him. He denied being married. Then, he told her that he'd "lost" his wife and that this would be his first Christmas alone. He gave Frey the same story when Sibley threatened to expose him.

On December 14, Peterson and Frey went to a formal party her acquaintances were hosting. She'd asked him how to introduce him to clients. He agreed that she could call him her boyfriend, and said he was monogamous with her. Meanwhile, Laci Peterson attended a friend's holiday party alone, saying that her husband had to work.

That night, Peterson and Frey had sex without birth control. He panicked afterward, telling her that he'd help raise her daughter but he didn't want kids and was considering a vasectomy. The next morning he said she wouldn't see him until the end of January, because he was going to spend the holidays with his parents in Maine and then meet with colleagues in Europe to discuss reducing his travel schedule so he could spend more time with her and her daughter.

Peterson's fears that Amber Frey would find out that he was married may have led him to hatch a terrible plot.