Police are investigating the theft of a bronze plaque from a monument at Mark Twain's gravesite in upstate New York.

Bryce Cuyle, superintendent of Woodlawn Cemetery in Elmira, says Monday that the 12-inch-by-12-inch likeness of the American writer was likely stolen sometime between Christmas and New Year's Day.

The plaque showing Twain's image was one of two on a 12-foot-tall, 78-year-old granite monument commissioned by Twain's daughter, Clara. The other plaque, of Clara's husband, was untouched.