Not "The Witcher". This is on 'zon, "The Murder at Roadhill House", there are 3 more episodes so far. Based on a 2008 book by Kate Summerscale.
Period 1860, in a crappy English village of Wiltshire, a family awakes to find a missing child (called a "baby" and kept in a crib, but he's nearly 4), and when he's found dead, early Scotland Yard is called, they send a sad-faced Paddy Considine as the improbably-named but historically real Mr Whicher, though the actor doesn't fit the character well:
Whicher was reportedly described by a colleague as the "prince of detectives".[2] Charles Dickens, who met him, described him as "shorter and thicker-set" than his fellow officers, marked with smallpox scars and possessed of "a reserved and thoughtful air, as if he were engaged in deep arithmetical calculations".[2] William Henry Wills, Dickens's deputy editor at Household Words magazine, saw Whicher involved in police work in 1850 and described him as a "man of mystery".
—wikipedia
The start's very slow, and often uses voice-over repetition to pad out scenes that would just be Paddy walking around looking at things. Later in the first ep, they send along a sergeant, "Dolly" (William Beck), which helps with dialogue, though he gets vanishingly little character development. The local authorities are unhelpful, hostile, closed-minded fools you'd expect of the still-medieval backwater English.
Whicher's not quite a modern, scientific detective, but he tries. And he's a bit moody, especially between cases he's as useless and dissolute as Sherlock Holmes; which is probably a modern back-adaptation from Arthur Conan Doyle's 1880s books.
The pacing is glacial, much plot happens off-camera, and an early version of spinning-newspaper headlines. Very little time is spent on backstory outside of the main suspects; I wonder if the book goes deeper, or if this is all there is.
Still, it's a good enough mystery, Whicher's worth watching, what-cha.
★★★½☆