Picture of Innocence

S10 E6: When a photo of DCI Barnaby with another woman is displayed shortly before her estranged husband is murdered, he becomes a prime suspect in the crime. To make matters worse, it appears that Barnaby visited the victim on the night he died, and a glass with his fingerprints on it is found at the dead man's home. As the evidence begins to mount up against him, will Barnaby be able to clear his name?