As usual, they are waiting for a body to turn up (maybe) or they are just assigning this case to the dustbin. They need to go to trial with this mountain of circumstantial evidence before the suspects die from old age. I can't believe the injustice.
I wonder if LE still has her car. Maybe there is DNA? Even her purse could have DNA on it. If it has the step-brother's DNA on any of these items, he has some explaining to do. I know it is a looong shot, but there are new techniques in forensics. Maybe they can add to that mountain of circumstantial evidence with some iron clad evidence. I'd follow the men around and confiscate their coffee cups, drinking glasses, forks or spoons from public places to get their DNA. I'd talk with their wives or exgirlfriends too.
Someone towed her car. The tow company was probably hired to tow it. Didn't LE try to track that business down to ask them who paid for the tow?? If they did and it was one of the suspects, who hired that tow, then there is a good chance for a successful conviction, IMO.
Just some thoughts.