MOO, the loss of that tip was gross incompetence.
It exposes our biases.
The action item, follow up on the girls he saw.
If it were magic, it works by directing your mind in one way while the slight of hand occurs. If it was a riddle, it relies on the brain's missing the detail. "If a rooster lays an egg on a rooftop, which way will it roll?"
Did we ever get clarification on the order and timing?
Did Richard Allen call the police station/tip line? Then Dulin was tasked with following up with him? Have we seen HIS report/note? Where does this cleared document fit in? Was it years later in his interviews that he described the group of girls (one taller, long hair, babysitting)?
By the looks of just the cleared document, is this what happened?
Dulin talked to Rick who clarified, said he saw girls, not Abby and Libby (lie), but the other ones? And that resulted in "lead cleared"?
No one thought to highlight -- hell, we've got a guy WHO WAS THERE exactly when the crime occurred -- but instead got all tangled up in which girls he says he saw?
Talk about hiding in plain sight.
I'm still confused how this didn't create a greater paper trail. Tragically, in the process of trying to streamline tips, interviews, different departments, too much was lost.
As much as I HATE how it played out and the devastating delay it caused, it was there to be found. Without it, this case likely would never have been solved and Rick would have taken his evil secret to his sorry grave.
Credit to the hero who found the tip and RECOGNIZED THE VALUE OF IT (her attention was drawn away from the cleared lead and details IMO by her brain focusing on a name/address she recognized, which have her a different angle to view it -- solving the saddest riddle ever told)
Three/four juveniles saw a man on a bridge.
A walker saw a man on a bridge.
A driver saw a man near a bridge.
Two girls revorded a man on a bridge.
How many men were on the bridge?
JMO