[Devil_Anse]

Great thought! I wonder if those who saw the footage of the patch of cement could tell us if the tire tracks looked like an automobile tire, or like a smaller tire--such as those auxiliary wheels?

[TexKat]

DA did you see the video at post #124. If not click on Bill Garcia. But you are not able to see tire tracks or at least I could not.

[RGSpincich]

The cement on the side of the canal(?). Just mixed, not set and the tire rolled through it, presumably while a vehicle was leaving. You see the problem, SP would be leaving before the cement set up. Wet cement used as an anchor or weight?
The timing seems all wrong to be mixing cement at that location if she is in the water. Even if he rolled a utility wheel through it, he spent alot of time in one spot waiting for the cement, oops, concrete to set up.
Maybe in the dead of night he felt safe there, though. Say 2AM 12/24. Mix it up at the back of the truck in a container on the ground. Transfer the concrete into the container holding the body in the back of the truck. Back the truck a little closer to the water, rolling through fresh concrete that had been spilled. Dump the sealed container off the back of the truck into the water. I don't know about this scenario.