As the Inspector Said by Syril Hare

Sonia French married Robert. The young woman was bored with the old man, she did not like her husband. But Robert didn't care about that. Soon Sonya had a lover, Charles Daryl. Rumors started to spread, and Sonya knew that Robert would soon find out. She knew that her old husband would never divorce her. He was a really rich man. On the contrary, Sonya and Charles had absolutely little capital. They thought killing Robert was a clever idea. There was a police officer who accidentally hinted that way when he told them to be on the alert, and there were a lot of bad people around. The lover was not an experienced criminals