Its very hard to see where EE are going with this purse and phone buried storyline, without Jay being found out at some point and with him already as a suspect from the CCTV footage if, or should I say when, Lucy's belongings are found then his fingerprints are going to be all over them.
Whether Jay and Ben were involved in some kind of mugging or whatever, Jay is the only one at risk and I can't see Phil allowing Jay to name Ben if he gets arrested by the police.
Using my imagination and moving forward a few months, I think what is happening this week causes a chain reaction of events that will lead to the eventual killer being found and my money is now firmly on Abi.
Firstly she has played hardly any part whatsoever in the lead up to all this but now suddenly with the Uni story and Jay planning on going with her and subsequently dumping her I think we'll see a different Abi, a change in her character leading up to the reveal.
If Jay does get with Lola I can see Abi finding out through Ben that he and Jay saw Lucy the night she was murdered. Ben will probably blurt out that they found Lucy's purse and phone and when they found out that she was murdered that night they panicked and decided to bury it.
Abi upset over the split with Jay then decides that she wants to get back at him for dumping her will then find the evidence and pin the murder on Jay, hence the sudden decicison to seperate them, all in the knowledge that she killed Lucy and can now get away with it as well as get back at Jay.
That is my theory anyway and the most logical outcome, otherwise why go to the lengths of the CCTV footage and burying of Lucy's things if at some point this has no bearing on the ending?