The key pieces of evidence presented at his 2004 trial included:
The Location of the Bodies: In April 2003, the remains of Laci Peterson and her unborn son, Conner, washed ashore in the San Francisco Bay, about a mile from where Scott Peterson admitted to taking a solo fishing trip on the day she disappeared.
The Unreported Fishing Trip: Investigators discovered Peterson purchased a boat shortly before the disappearance and did not have a valid fishing license, raising suspicion about his sudden interest in fishing on Christmas Eve.
Suspicious Behavior and Flight Risk: Prior to his arrest, Peterson altered his appearance by dyeing his hair blonde, and was apprehended near the Mexican border in San Diego. In his vehicle, police found camping gear, nearly $15,000 in cash, multiple cell phones, and his brother's identification.
Secret Affair: The prosecution heavily highlighted his extramarital affair with Amber Frey, using it to establish a motive that Peterson wanted to rid himself of his family life.Lack of Forensics: The case notoriously lacked direct evidence—there was no murder weapon, no DNA placing Laci in his truck or boat, and no identified crime scene.
The above is a listing from a Google search. As in most murders, motive is a prime consideration, and he definitely had motive with the extramarital affair. Just my point of view, but a person that is willing to cheat on their selected life partner, and particularly one that is pregnant, is fully capable of murder.
For me, it was his suspicious behavior from the start that made my skin crawl. He did not behave like a man genuinely concerned about the wellbeing of his wife. His demeanor was completely detached from such a mindset. While the evidence was largely circumstantial, when you put the pieces together, I say he was as guilty as hell.
