Who Do You Think You Are? (10.15pm RTÉ One) features veteran BBC news reporter and world affairs editor John Simpson in search of his roots. Tennis: Wimbledon 2015 (11.30am BBC Two) features live action from the fourth day. And where there’s a murder there’s usually a weapon. It’s the piece of evidence that can hold all the clues needed to catch the killer. Final episode of Catching History’s Criminals: The Forensics Story (9.00pm BBC 4).

Tennis: Wimbledon 2015

11.30am BBC Two

Sue Barker introduces live action from the fourth day of the 2015 Wimbledon Championships. Great Britain’s Andy Murray was champion in 2013, but came up short in his defence last year when he was knocked out by Bulgaria’s Grigor Dimitrov. At this stage of the men’s singles last year, though, Murray thrashed Slovenia’s Blaz Rola 6-1, 6-1, 6-0. Live Wimbledon coverage also takes place from 1.45pm to 6pm on BBC One.

Catching History’s Criminals: The Forensics Story

9.00pm BBC 4

Where there’s a murder there’s usually a weapon, this final episode explores. It’s the piece of evidence that can hold all the clues needed to catch the killer, and shine a light into the mind of the murderer. In this final episode, surgeon Gabriel Weston (pictured) investigates the forensic advances that have elevated the murder weapon from mere evidence to key witness.  

Scientists have developed 3-D laser scanning which can be used to reconstruct the exact sequence of events at the scene of a gun crime - and decipher whether a shooting was murder or self defence. Gabriel will also investigate the pioneering chemistry that can now determine where in the world someone has spent time, based on just a few strands of their hair.

Who Do You Think You Are?

10.15pm RTÉ One

Veteran BBC news reporter and world affairs editor John Simpson always thought his great grandfather was Samuel F Cody, famous for being the first person to fly in Britain and a Wild West entertainer. It was only later that John discovered that his great grandmother, Lela King, had run off with Cody, taking her children with her. John follows the trail of his adventurous great grandmother and her life with Cody, the cowboy turned aviator. He also investigates what happened to the husband Lela left behind, John's real great grandfather, and makes a shocking discovery.