I can tell you for sure that every government in the world has been involved in cover ups.

I can also tell you that if officials and candidates of a major politcal party are implicated in a conspiracy to cover up a murder, especially if during an election campaign, people will inevitably want to discuss it.

The fact that Loyalist and Republican paramilitaries often mrder each other is not all that interesting to outsiders. Sorry, but that is how it is.