From Netflix:

Haunted by an unsolved murder, brilliant but disgraced London police detective John Luther breaks out of prison to hunt down a
sadistic serial killer.

From Netflix  you can stream this 2 hour 10 minute complete film.

Idris Elba has made several Luther films, all of which are watchable, tense crime films. This particular story is disturbingly violent with some ugly scenes. At the end Luther and the serial killer battle to the end in a mansion in the snowy wilderness. Amidst the snow there are clear patches of ice underneath which we see the dead bodies of the killer’s victims.  You are warned.