Protection Season 1

Liz Nyles is a witness protection officer in charge of looking after Jimmy, Helen and Amy McLennan in their assigned safe house. Jimmy has been offered witness protection for testifying against Edward Crowther, an untouchable crime boss who's finally being tried for murder. Liz is shocked when she hears there's been a shooting at the safe house and her key witness Jimmy has been shot. But worse, her colleague DS Paul Brandice, with whom she's been having a secret affair, was also at the house and has been shot too. Brandice had not been working on the case, there is no reason for him to be involved, so why was he at the address?