"Old Dogs" A spate of violent dog killings 30 years ago provoked an outcry from the public, but the investigating team was never able to identify the killer. When a dog is found dead on Hampstead Heath, with the same MO as the original killings, the Unsolved Crime and Open Case Squad (UCOS) is asked to re-examine the case: no-one else in the Force wants to know. Reluctantly, Pullman and her team pick up the baton. Standing and Lane set off to visit the original suspect, John Fletcher, who works at a local abattoir. Much to dog-loving Lane's disgust, Fletcher does nothing to disguise his hatred of man's best friend, which is all Lane needs to convince him that this must be their man. Lane, already struggling to cope with the cruelty of the killings, is left shattered when his own dog, Scruffy, dies.