Some TV detectives – you know who you are – are bulls in the china shop, getting information and solving crimes by a sheer show of power.
DCS Steve Wilkins (Luke Evans) isn't that kind of cop in The Pembrokeshire Murders, a three-part series that becomes available Tuesday on BritBox.
The story, created and directed by Nick Stevens, is based on notorious real-life crimes in Wales. They're cold cases, 17- and 20-years-old, by the time Wilkins decides to re-tackle them.
A couple was murdered in 1986, and while detectives felt they had a strong suspect in John Cooper (Keith Allen), they never could assemble enough evidence to charge him.
It's now 2006, and Wilkins is looking at another unsolved murder from 1989. He has a sense it was the work of the same killer. His bosses aren't keen on making a big thing about this since it doesn't make the police look good to be dredging up cases they didn't solve, so Wilkins has to start quietly. Which is fine because that seems to be his style anyhow.
Cooper, it turns out, has been in prison since 1989, for a string of robberies. He's up for parole and seems to have convinced the parole board he's a model prisoner.
This puts Wilkins on the clock. He must build a case against Cooper, if he can, before he's released back into society.
Wilkins gets a break – though it doesn't look that way at first – when local journalist Jonathan Hill (David Fynn) independently tells the police he wants to do a documentary on the unsolved 1986 murders.
Wilkins would prefer that Cooper not get the idea anyone is still looking into these crimes, so he cuts a deal with Hill: Hold off on the documentary, and if we nail Cooper, you get the exclusive.
TV detectives and the media have been known to cut deals before, and half the time, the two parties seem to end up dating. That's not the deal here, and perhaps because of that, the strictly-business relationship plays an interesting role in the resolution of the case.
Naturally, there are complications along the way, including the role of Cooper's bitter son, Andrew (Oliver Ryan), and Cooper's wife, Pat (Caroline Berry).
Wilkins has some baggage of his own, like all TV cops, but Pembrokeshire Murders sticks, primarily, to the detective part of the case. That keeps the story moving at a good pace as Wilkins and his team search for any little thread of evidence that might raise his intuitive sense of Cooper's guilt to a level that would persuade a judge or jury the guy needs to be put away.
Some of what the detectives find is literally little threads, tiny pieces that yield DNA it was not possible to detect in 1986.
One of the other key breakthroughs, however, will prove as much of a surprise to viewers as it does to Wilkins.
As a bonus for viewers, BritBox also unveils on Tuesday a documentary on the making of the series and the real-life pursuit of the killer.
It's a good crime mystery package.