Testimony in the double murder trial of Scott Peterson focused on how he reacted after he realized that he was being followed, but the question raised concerned whether he knew it was the police following him, or the news media.

Prosecutors claim that Peterson was acting like a guilty man when he discovered he was being tailed, but defense attorneys tried to point out that Peterson thought it was being followed by private investigators hired by The National Enquirer, which would explain his erratic driving.

Seven different undercover agents testified last week about their observations will assigned to follow Peterson. They testified that Peterson made three trips to the marina where his wife and unborn son's bodies later washed up, but they also said he spent hours at a volunteer search center and posted missing-person fliers several locations.

Testimony this week is expected to focus on mitochondrial DNA evidence found in Peterson's boat.

See Modesto Bee: Peterson Knew He Was Being Followed

Background: The Scott Peterson Trial
See Also: More Headline Cases