I have a theory... just go with me for a minute.
Amber is/was a bright girl. A "friend" set her up with Scott Peterson. That friend, Shawn Sibley, met Peterson at a pesticide convention and thought he would be perfect for Amber. Sibley did not know that Peterson was married. This is in 2002. Amber had a very close friend who was a homicide detective with the Fresno Police Department. Amber also had a daughter, and she was admittedly looking for a serious relationship. She was immediately taken with Peterson. Can we honestly believe that after those first couple of dates, Amber didn't call in a favor to her friend, Richard Byrd, the homicide detective, and have him check out Peterson? Now, according to the record, he did this for her on December 29, five days after Lacy's disappearance, just about a month into Amber and Scott's relationship. But allow a one-week window for human error. That would mean the conversation could have happened on December 22 or 23, right?
Amber was a massage therapist, and she drove a minivan. How difficult would it have been for her to knock on Lacy's door that morning after watching Scott leave and Lacy arrive back at the house, present her with her card, and tell her that her husband, Scott, had arranged for her to have a relaxing in-home prenatal massage as part of her Christmas gift? She brings in her massage table, gets Lacy in a vulnerable position, and kills her either by injection or strangulation. They make massage tables with locking wheels so that Amber could have opened the back gate - letting the dog out accidentally, pulled her van in, wheeled Lacy out to the minivan, and dumped her body in the back.
Everything about the case was publicized - this was the first trial by media case, thanks to the internet and 24-hour news. She could have been very calculating and dumped the body exactly where he had been fishing.
I know I will catch hell for this, but for me, Amber is reasonable doubt - watch the press conference where she delivers her statement, particularly her body language and facial movements when she says Connor's name. I have always wondered why they didn't look into her with more depth.