It was watchable ............ and enjoyable compared to lots of the rubbish on TV. It didn't explain anything to conclusion with regard to how Jane's mum knew her killer ........... and she clearly did from how she greeted him at the lakeside, there was no struggle or attempted assault, he just cracked her round the head with a rock immediately.
I knew how he had mismatched the blood DNA test having been a bone marrow donor - however, I believe, as routine, the police would have taken saliva also for exactly this reason (some organ transplants create chimeras too)
Decent acting though, wishy washy story. Billed as a thriller, it was not imho - who was the guy playing Jane's husband? I know him from somewhere else on TV ..............