Man, it's got to be the boat launch canal ot the east. Old discussion, I know, but it's pretty hard to stop on the Whiskey Bay bridge and dump a body and bike without having a car come upon you. You would almost have to spend your whole time on the drive out there trying to maximize the distance between you and the car behind you to give you a cushion to stop.
But then the bike supposedly is placed under the Basin bridge - not the Whiskey Bay, yet is found in water. I'm telling ya, if that bike was PLACED, then those perps had a boat. There's no way to place it there without a boat. Now you could DROP the bike from the Basin bridge. I truly don't think the bike was dropped from the Whiskey Bay bridge, because this had to have been done at night, and at night, what are the chances that they drop the bike at the perfect spot so it ends up only partially submerged?
I think they're going to find that you had two perps who jumped out. One tossed the bike over the right side (shallow side) of the Basin bridge, while the other dragged her to the left (deep) side between the twin spans. They had to act fast, so I bet the passenger screwed up and threw the bike over the right side not realizing how shallow it is there.
On the other hand, if they stopped and did it at once, you'd think that bike and body would be close, and would have been found.
She still may not be there.