New Tricks - Season 4 - Eps 5: Powerhouse
The team reinvestigates the 1950s murder of a young wages clerk at Battersea Power Station. Richard Dunne was hanged for Frederick Tully's murder, but his granddaughter, Hannah, is waging a campaign to have Dunne posthumously pardoned. The discovery of a suitcase containing used fivers in the attic of the Tully home sheds new light on the case, revealing a possible blackmail plot. A trace on the used fivers reveals that they should have been destroyed in the Battersea Power Station furnaces back in the 1950s, but were actually being saved by Douglas Murray, a friend of Tully's. It also becomes clear that the Battersea furnaces were being used to destroy other sensitive documents as well as used bank notes. When the team discovers a classified document relating to a massacre of civilians carried out by the British Army in Kenya, they uncover a blackmail plot spanning more than 50 years.
About New Tricks

Title: New Tricks
First Air Date: 2004-01-01
Last Air Date: 2015-09-29
Status: Ended
Rating: 7.4/10 (from 54 votes)
Language: EN
Seasons: 13
Total Episodes: 107
Network: BBC One
Genres: Drama, Comedy
Production Companies: Wall to Wall, BBC
Synopsis
New Tricks is a British comedy-drama that follows the work of the fictional Unsolved Crime and Open Case Squad of the Metropolitan Police Service. Originally led by Detective Superintendent Sandra Pullman, it is made up of retired police officers who have been recruited to reinvestigate unsolved crimes.
Cast

Dennis Waterman
Gerry Standing

Tamzin Outhwaite
Sasha Miller

Denis Lawson
Steve McAndrew

Nicholas Lyndhurst
Danny Griffin