Michael Gilbert 
Sky High [PDF ebook] 

Tim appears to have had an exciting war, but is fairly secretive about what he had been up to. He lives in a sleepy village with his mother Liz, who is concerned about him not least because he is equally unforthcoming about the job he has in London. Meanwhile, the local choir rehearses, but there are sinister undercurrents and not all of its seemingly respectable members may be have been entirely honest about their past. Then a house in the village explodes, killing the occupant with whom Tim had previously quarrelled. The police immediately latch onto the fact that Tim worked with explosives during the war. Moreover, he could possibly be a suspect in respect of a series of country house burglaries. With the finger pointing at him, should Tim explain, investigate, or solve the mysteries? The final twist, as always, remains with Gilbert until the reader stumbles across it.