Yes, agreeing ^. LE saying 'Mr X is not a suspect in the ABC crime' is not the same as saying 'we have cleared Mr X of involvement in the ABC crime.'
Even if LE says 'we've cleared him,' if 6 mo, 1 yr, or 5 yr from now, more evd against Mr X is developed - technology advances, witness or co-conspirator comes forward, etc - that earlier LE stmt does not preclude prosecuting Mr X. That's why LE rarely makes such stmts (although there are exceptions). Think about successful prosecutions of some cold cases. LE's prior stmts like that prob'ly/certainly not admissible at trial, but pre-trial, defense atty's can fuss about it in media.
Over decades of reading many (1000+) true crime books, I've developed expectations of years-long time frame for crimes, investigations, arrests, PC hearings, pre-trial procedures, trials, sentencing, etc. As science & technology evolves, there are more tools for investigating & prosecuting. Imo, the DNA match that put DDW in LE's spotlight is an anomaly, in that it happened so fast. Likely that other arrests, if any, may be far down the road. Or not, IDK.
JM2cts, could be all wrong.