Yah I have always thought that they had a partial dna profile at best. The problem with partial Dna is that it can match to thousands of people. JMO
ETA I'm not convinced that Dna evidence is going to be what breaks this case open. I think its going to be one of those deals where something is said by BG when he's drunk or off the cuff and somebody reports it to LE. Or that somebody that is close with BG feels wronged in some way and spills the beans to LE after they no longer have ties to BG.
ETA or if it is dna its going to be some kind of new technology that replicates partial DNA profiles etc.
I think it will be physical evidence(possibly DNA) that is what is going to make this case. All police have to do is find this person and the picture, voice, or physical evidence at the scene should help make their case. That is probably why the case is so frustrating because they have the evidence but not the man.
This is why police have to be on the guard for confessions. People that say things when they are drunk will just deny them later. Rumors that someone said something are considered hearsay. Boyfriends, girlfriends, husbands, and wives will unfortunately waste valuable police man hours in order to get their significant other in trouble. Just because someone says something does not mean anything without proof.
Take the missing person case of Danice Day on the show
Disappeared. This case happened in Colorado in January 2002. After she disappeared police got hold of a rumor that the boyfriend's father had to help his son dispose of the body after the son killed her. Both the father and son were brought in for questioning and denied it. At one point police got the father to admit during questioning that if someone was going to bring down his son it was not going to be him. So police pretty much knew that since Danice Day was last seen at her boyfriends house because they had kids together that it was most likely the boyfriend. It took about 7 years of police following the boyfriend around before they could arrest him for something else and offer a plea deal in exchange for Danice Day's whereabouts. The boyfriend told them where he put her remains. Her remains were found in a blue barrel in an Arizona lake around June 2009.
The point is that while a rumor of who may have done it would help police it will certainly not lead to a conviction unless the accused provides evidence and a confession. The boyfriend in the Danice Day case never admitted he murdered her. He only pleaded guilty to a manslaughter charge,
even though he led them to her remains.
So in this case I think they just need to find the man on the bridge.