Nope…… in true line of duty style, halfway through the penultimate episode they will introduce a new character who hasn’t been eluded to previously – turns out, they did it. Probably an evil twin brother or something, or somebody will find an old photo picturing said new character with one of the victims.
All of your painstaking attention to the storyline, evidence and analysis of the potential suspects will turn out to be completely wasted. All of those little things that don’t quite make sense that you are trying to piece together – nah, we won’t even mention those again and just leave them hanging/unresolved at the end.
LoD is the equivalent to a locked-room mystery, but in the end they just write-in a hidden trapdoor under the rug.