I think if the police had found any link between Vincent Tabak and Claudia Lawrence, we would know about it by now.

There is no evidence that Tabak had Asperger's. He might have been late in finding a girlfriend because he had been busy studying! From what I read, he went to parties, partook in sports with other people, etc. Not sure he was a "loner" at all, even if he had been as a child (which wouldnt have been that surprising, since he was MUCH younger than his siblings).

There is no really firm evidence that he killed Joanna Yeates, either. Whatever DNA they claimed to have found would not have been enough to convict him (so I have read). Without his so-called confession, if it really WAS a confession, he could well have been acquitted.

It was very convenient to charge the next door neighbour, having just messed things up with the landlord.
Tabak definitely didn't have Aspergers. The media love to portray aspergers people as being the types who will commit violent acts on a whim, but it really isn't like that.

Overall, our media and particularly newspapers did not come out of the Jo Yeates case looking very good did they! Look at Chris Jeffries.