The Murder on the Links by Agatha Christie

Her rancour against the older woman showed plainly in her voice, and I could well understand that it must have been a bitter blow to her when her only son showed signs of falling in love with the daughter of her rival.

The Secret Adversary by Agatha Christie

The two men departed and the door slammed. Tommy was left to his meditations. They were not pleasant ones. Already his limbs felt cramped and stiff. He was utterly helpless, and he could see no hope anywhere.

The Man in the Brown Suit by Agatha Christie

The thing is very extraordinary. Where did the girl go? She walked out of the hotel, fully dressed, about ten minutes past eleven, and she was never seen again. The idea of suicide seems impossible.