The evidence against Luke is that he found her body first, he looked a bit dodgy, his family were “well known bad apples” and he had books on serial killers esp the Black Dahlia. Serial
Killer movies were a huge thing at the time, the Black Dahlia was the main story in one, it wasn’t a niche thing by any means. Ed Gein Fan Club T-shirts were mega popular. In the late 90s many teenagers were “ironically” into satanism and serial murder and went on to be teachers and accountants.
Jodis adult brother was sectioned numerous times and there was a lot of talk locally about him potentially abusing Jodi.
Her sisters adult boyfriends semen and blood traces were found on her bra and underwear, he was second to find her body and his police interview is worth reading.
Then there is another random man that has not been named that admitted to wanking off into a condom (?) which he then threw over the wall onto her body which he was unaware was there

Luke was 14. How many sadistic killers start to murder at 14? And are somehow stupid enough to find the body but smart enough not to leave DNA traces?
i’m sure luke was well known to the police locally but I don’t believe he did this - there are at least two much more likely suspects.