Shetland - Season 4 - Episode 6
Season Finale - Troubled by historical DNA evidence results, Jimmy has to face the fact that Duncan may have been involved in Lizzie Kilmuir's murder, and potentially Sally McColl's as well. A shocked Duncan is brought to the station for questioning, hurt that Perez would even think him capable of murder. However, the detective knows Duncan's lying - perhaps not about the murder, but about something else significant. So when Duncan finally admits he had an affair with Donna, it's not long before a bombshell is dropped.
About Shetland

Title: Shetland
First Air Date: 2013-03-10
Last Air Date: 2024-12-11
Status: Returning Series
Rating: 7.5/10 (from 174 votes)
Language: EN
Seasons: 10
Total Episodes: 50
Network: BBC One BBC Four
Genres: Crime, Drama, Mystery
Production Companies: ITV Studios, BBC Scotland
Synopsis
Created from the novels by award winning crime writer Ann Cleeves, Shetland follows DI Jimmy Perez and his team as they investigate crime within the close knit island community. In this isolated and sometimes inhospitable environment, the team have to rely on a uniquely resourceful style of policing.
Cast

Ashley Jensen
DI Ruth Calder

Alison O'Donnell
DS Alison 'Tosh' McIntosh

Steven Robertson
DC Sandy Wilson

Lewis Howden
Sgt Billy McCabe

Stuart Campbell
Malcolm Kidd

Robert Jack
Ian Bett

Vincent Regan
John Harris

Ian Hart
Euan Rossi

Sarah MacGillivray
Annie Bett

Leeroy Boone
Anton Bergen