Double Fault by Judith Cutler
When a child goes missing at the local tennis club on the day when several skeletons are unearthed on an Ashford building site, Fran Harman finds her caseload heavier than ever at a time when the force is cripplingly short-staffed and she has a less than supportive new Chief Constable to contend with.
Enjoying a game of tennis with his fellow Golden Oldies when the girl disappeared, Fran's partner Mark can't help blaming himself for not keeping a closer eye on her. Sucked into the kind of desperate police search he thought he'd left behind on retirement, Mark enlists the help of the Oldies to find young Livvie before it's too late.
Meanwhile, a further shocking discovery in the skeleton case suggests that a serial killer may be lurking rather closer than Fran would wish.