We know that Conner did not wash ashore, and his body was placed on the Richmond Jetty shortly before he was found. The evidence is non-conclusive regarding Laci: she may have been placed in the Hoffman Bay on the night of the 12th/13th, or she may have been placed exactly where she was found during the early morning hours of the 14th.
These facts cause us to ponder some disturbing questions:
Why were they put on the Richmond Jetty and Point Isabel?
To incriminate Scott Peterson. He was clearly the only suspect. His fishing trip was well-publicized. Who didn't know that Scott Peterson went fishing at the Berkeley Marina on December 24? The Bay searches from late December through early April were well-publicized, and we knew they were searching in the Berkeley Marina, along the fishing route, and also in the Richmond Turning Basin (Chevron shipping channel). False reports had been given of bodies found. It didn't take a genius to know that finding the bodies in that area, anywhere in that area, would automatically incriminate Scott Peterson. Whomever planted the bodies there didn't need any specialized training or information -- anywhere along the shoreline from the Turning Basin to Berkeley Marina would have worked.
Why take the risk of moving the bodies?
It seems a foregone conclusion that whomever abducted Laci and murdered her and Conner was getting away with it -- Scott Peterson was the only suspect, and other leads had been summarily dismissed by the MPD with little or no investigation. So, why take the risk? Why not leave well enough alone?
Suppose the bodies were at risk of being discovered, and that discovery would force the MPD to look at other suspects. Suppose the bodies could be linked to one of the Laci-sightings the MPD ignored.
Suppose the bodies were actually found somewhere else, at a location linked to one of the Laci-sightings the MPD ignored.
Who moved the bodies?
Who had the most to lose if the bodies were found elsewhere? Who had the most to gain if the bodies were found at the Richmond Jetty and Point Isabel?