Another cool story, bro. A valid contemporaneously documented chain-of-custody either exists from the beginning or it does not exist at all. It can't be "re-created" after the fact.
Besides, the jacket allegedly found in the car park isn't evidence of anything, so it really doesn't matter anyway.
How many bad guys do you figure were involved altogether in the planning, the "patsy-ing," the shooting, and the all-important Cover Up?
Couple hundred?
More?