Late, Late In The Evening (LIN) (Linford Mystery Library)

When a double murder is suddenly committed in the Oxfordshire village where young Ken and Meg Clifton spend their school holidays, there seems little motive for either death, and no connection between the two. The general opinion is that the village contains a homicidal maniac. Mrs Bradley thinks otherwise; but even with Meg and Ken's eager assistance, she can make little progress until her enquiries uncover the impudent impersonation of a man who died five years previously...