Killer Dolphin by Ngaio Marsh

Death at the Dolphin is a detective novel by Ngaio Marsh; it is the twenty-fourth novel to feature Roderick Alleyn, and was first published in 1967. The plot centers on a glove once owned by Hamnet Shakespeare, on display at a newly-renovated theater called the Dolphin; the novel was published as Killer Dolphin in the United States. Several characters from the novel return in Marsh's final book, Light Thickens.