I’m the same - it’s definitely the hardest bit to rationalise for me. However, there are a few things. 1) Jen was 18 years old and pretty naive with regards to legal matters - I doubt she would have been fully aware that saying she helped her close friend dispose of some spades would translate to her implicating herself as an accessory after the fact. 2) In her first interview with police, she denied knowing anything about the murder and burial. She then met with the police again, with lawyer present, and provided details to corroborate Jay (keeping in mind there were significant inconsistencies between Jen and Jay’s testimony). It is entirely possible that the cops, who had gone so far as to coach Jay’s testimony, asked Jen for corroboration whilst assuring her that she wouldn’t face any charges. I think if cops are capable of corrupt dealings with Jay, they are capable of corrupt dealings with Jen too. 3) I don’t think people appreciate how close Jay and Jen were - she said they were “inseparable” and she “would do anything” for him. I do think it’s feasible that a naive 18 year old who deals drugs and is aware of her vulnerability to police would help corroborate her close friend if police pressured her enough. Again, she’s not saying she had anything to do with the murder, she’s saying she got some calls from Jay and helped him clean up. Given the extent of police corruption in this case - I don’t actually think it’s too much of a stretch that they also coached Jen so that they had an additional witness testimony to bolster their otherwise very sketchy case.