Anna the Adventuress by E. Phillips Oppenheim

There was a strange and ominous murmur of voices, a shuffling of feet in the gallery, a silence, which was like the silence before a storm. Anna, who had sung the first verse of her song, looked around the house, a little surprised at the absence of the applause which had never yet failed her. She realized in a moment what had happened. Even though the individual faces of her audience were not to be singled out, she had been conscious from the first moment of her appearance that something was wrong. She hesitated, and for a moment thought of omitting her second verse altogether. The manager, however, who stood in the wings, nodded to her to proceed, and the orchestra commenced the first few bars of the music. Then the storm broke. A long shrill cat-call in the gallery seemed to be the signal. Then a roar of hisses. They came from every part, from the pit, the circle and the gallery, even from the stalls. And there arose too, a background of shouts.

"Who killed her husband?"