A Pact with Satan by 'Leonard Holton' (Leonard Wibberley) (1960)
A very big-C Catholic mystery, the second of eleven that Wibberly wrote about Father Bredder. Bredder is a former marine turned priest. Now in his forties. he is assigned the chaplain of the Convent of the Holy Innocents and its school with 120 young girls. Bredder is very devote and literally believes in Satan. (although this Satan uses humans to work his evil) and Hell. Bredder is quiet, calm, unassuming, and sincere, reluctant to get on the bad side of the stern (she's British, you see) Reverend Mother Teresa. The girls in the school adore Bredder and will often turn to him for their problems.
Bredder is visiting by Mrs. Wentworth, a woman whose husband had recently died in a fiery car accident. The widow is not a Catholic but understands that Bredder is a good person to bring a problem to. She tells Bredder that her dead husband is trying to kill her. Already she has had her mattress soaked with gasoline and the gas turned on in her kitchen. Her husband she says, was very much in love with her, and had said that he should he die, he wanted her to also die so they could be together for eternity. Bredder naturally doubts her story. He suggest psychiatric help but she refuses to hear of it, insisting that it is her dead husband who is trying to kill her. To placate her, he promises to meet with her later that day.
Breder then goes to his friend, homicide Lieutenant Louis Menardi, to discuss the problem. Menardi, a widower, asks Bredder for suggestions for a 13th birthday present for his daughter Barbara. (She's too old for toys and too young for makeup and -- let's face it -- men can be clueless; but Barbara is a student at Holy Innocents and Menardi thinks Bredder might be able to gets some hints from her.) Bredder promises to help Menardi and Menardi promises to accompany him on his vist to Mrs. Wentworth. The visit, alas, reveals nothing and Bredder and Menardi are convinced that the widow is suffering from mental problems. Bredder, however, does notice and old book on display at the Wentworth house and, curious, he borrows it. The book was one that Wentworth was reading before his death and one that his widow is now looking through: A Popular Display of the Wonders of Nature. Being a Selection from the Transactions of the Royal Society of London by the Reverend C. C. Clarke. The book opened naturally to the account of a mid-18th century Italian Countess who died in her bed of spontaneous combustion; her husband had died in a similar manner three months previously. The story seemed to prefigure both what happened and was predicted by the widow to happen in present day Los Angeles.
Bredder decides the best thing to do is to write the widow and strongly suggest that she seek psychiatric help. In the meantime, the curious prient also wrote the vicar of the Italian town where the couple had supposedly been immolated in 1748. For his part, Menardi decides to investigate Wentworth's death. A dentist, he had driven to San fRancisoc for a dental conference and, on his return, lost control of his car. The crash ignited a can of gasoline that he always carried in the trunk and his body was burned beyond recognition; he was identified by documents and through a dental match. Wentworth had a history of serious heart problems and it was assumed that a sudden attack had caused the crash.
During the week after Bredder had sent the letter to Mrs. Wentworth, his conscience was plaguing him, He felt that he had unfairly dismissed the woman's concerns and that she deserves to be faced in person. He heads out to the Wentworth house. The door is unlocked and Bredder sidcovers the charred body of the woman...
Throuw in a secret club called the Innocent Investigators, with the young students honing their detective skills. Add a phosphorus beer can bomb that had been left at the convent and a silenced bullet that wounded Bredder in the should ouside the convent, and you have a very readable (although, to me, perhaps a bit too much telegraphed) puzzle that should please a lot of mystery fans.
Wibberley is probably best known for his novel The Mouse That Roared and its sequels. Among his many other book was A Feast of Freedom, in which a primitive tribe unknowingly eats the Vice president of the United States.