So many of these cases seem to start with the presumption of guilt and that can obviously be an issue for justice. I'm not saying that definitely happened here, I don't know enough about the investigation to be able to. But it does seem like there was a lot of attention placed on Luke immediately, focus no one else seems to have received.
Give me a list of 2 or 3 cases you are referring to.
The police interviewed over 3000 people in this case. And as I've already pointed out, those closest to
jodi would have fallen under the header 'suspect' until eliminated. I also imagine the police saw something or sensed something about Luke that bothered them when they met with him that night. I'm sure they had their reasons for asking him questions that night.
With regards the course of justice, as a member of the public, I would have expected Luke to have been one of the first questioned - based on the evidence adduced that Jodi was last seen on her way to meet with him on the path.
It would have bothered me if the police hadn't followed this up as soon as they were able.