how would that have anything to do with anything?
He set up the murder in order to investigate it, in order to use the LA CID to get to the drug/meth target Ledoux. Hence why the guys in 2012 are, or seem to be investigating Rust. They don't seem so interested in Ledoux (or even that Ledoux might have committed or had something to do with the 2012 murder), more how Rust was in pursuing Ledoux.
Or what ......even better, Rust never was a cop. They didn't really have any back ground on him coming from Texas. His "files" were sealed. (even in 2012). He was just out to get Ledoux because of some drug deal gone bad???? Or maybe he was a cop that got so far into the undercover, he just switched over (broke bad).
I don't think this is going to be a simple murder solving case. It has something to do with Rust and 2o12, not just the 1995 murder. It's gonna have some out of left field twist. I'm just trying to think of something that would be way out there.