Why was Burgess not arrested 10 years ago before killing the last victim?

As said, 10 years before the current events in Luther S01E03, Burgess (the killer) has been spotted by the police thanks to an anonymous tip and an undercover cop was sent to him.

It's not explained exactly what the cop did, but from the conversation between that cop and Luther later in the episode, we understand that the undercover cop somehow interacted with Burgess - he knew what Burgess thought of "bodily fluids" and that they "had to be taken into the body" (I guess, by Burgess) etc, etc.

That looks like the undercover cop had a clear picture of what Burgess was up to.

Why was it not enough for the police to arrest Burgess at that moment before the undercover cop beat him and it all went public?

I might not know something about the way undercover policemen work, but it seems a bit illogical to me

plot-explanation luther

Best Answer

The attempt to prosecute Burgess failed because of the actions of the undercover cop

Burgess was a careful murderer (as shown later in the episode). He was very good at eliminating forensic evidence of his crimes. So, after the initial murders, the police did not have enough evidence to convict him. Hence the use of an undercover policeman in an attempt to gather more concrete evidence to procure a solid case that would stand up in court.

But Burgess may have known about the cop (this is not entirely clear but Burgess is very smart). Whether Burgess knew or not, some event provoked the undercover cop into a violent act and Burgess was beaten badly. This completely undermined the case against Burgess (possibly because any evidence presented by the undercover policeman was regarded as entrapment or, possibly, because he had not gathered enough concrete evidence before the incident to ensure a conviction).

We know this because Burgess actively boasts (during a press conference in the middle of the current investigation) that he had previously been exonerated and the police are trying to unfairly persecute him. This makes it harder for Luther and the police to pursue their current investigation.

The point is that the police can't prosecute someone successfully even if they are very certain of their guilt unless they can find enough solid evidence that will stand up in court. Luther only finally succeeds by using some dubious tactics to convince Burgess that he hasn't cleaned his murder scene sufficiently and then catching him at the murder site with the body. That is strong enough evidence to convict and Burgess, though a victim of entrapment, can't prove that as none of the evidence of Luther's scheme is available.