I would take those press reports with a massive pinch of salt.
Was/could Shane have been certain that Luke was not in the house at the given time?
John, what are your thoughts about the lie detector tests that both Luke and his mother passed?
I, myself have always been quite sceptical about such tests, but the fact that they both passed causes me to wonder a little.
Shane was absolutely positive he wasn't in the house as he was looking at porn in his bedroom and was listening for anyone coming into the house. It wasn't a big house by any means so it would not have been very difficult to hear someone come in and start messing around in the kitchen as Luke claimed he did.
Bottom line is he has no alibi and was identified by two witnesses near the murder scene. Some minutes later he was seen again by several others further up the road. The chances of two almost identical youths wearing the exact same clothes being on the same stretch of road at almost the same time is incredibly small.
Mitchell was a troubled child by all accounts who was left to run wild and do more or less whatever he wanted. He was a heavy user of cannabis and had all the paraphernalia in his bedroom for weighing and bagging the drug for resale to other schoolchildren. The slaying of Jodi wasn't by any means the first time he had threatened a young girl with a hunting knife.
The polygraph test or lie detector is merely a gimmick fit only for daytime TV programmes. It has no relevance and no legal status.