It's the independence 'I most value,' Prichard says

Murder—in the mews, at the vicarage, along the Nile or on the Orient Express—pays off handsomely, as Mathew Prichard can testify. Whodunit for him? His grandmother, the late Dame Agatha Christie. Prichard, 34, is chairman of Agatha Christie Ltd., the company that collects royalties and leases the rights for most of Dame Agatha's 88 books, 17 plays and 100 or so short stories. Prichard also received a very special gift when he was only 9. His grandmother signed over to him sole rights to her new play The Mousetrap. The mystery thriller has turned out to be the longest-running drama in London's history. More than 25 years later it is still being performed eight times a week in St. Martin's Theatre. Ticket sales in London alone—not to mention the 41 other countries where it has been staged—amount to more than $7 million.

Despite the author's death in January 1976 at 85, the tide of Christiemania continues to rise. The huge success of the 1974 film Murder on the Orient Express spurred sales of all Christie's books; there are now about 400 million copies in print. Curtain, the final chapter in the life of sleuth Hercule Poirot, and Sleeping Murder, the last Miss Marple mystery, were both best-sellers. Paperback rights to Christie's An Autobiography were just sold for $250,000, and the movie Death on the Nile (starring Bette Davis with Peter Ustinov as Poirot) will be released in October.

Besides Mousetrap, Dame Agatha parceled out exclusive rights to other works to relatives and friends. Her surviving second husband, archeologist Sir Max Mallowan, was given Sleeping Murder, while Curtain's royalties go to Agatha Christie's only child, Prichard's mother, Rosalind.

As watchdog for his grandmother's estate, Prichard is thrilled about all the ongoing projects except one—Agatha, a film in which Vanessa Redgrave plays the author and Dustin Hoffman a fictional American journalist. Agatha deals with the mysterious 11 days in 1926 when she disappeared after discovering that her first husband had a girlfriend. Dame Agatha always insisted that she lost her memory, and Prichard echoes that explanation. In any case, the subject was taboo within the household. "I never exchanged a word on it with my grandmother," he says. The family has gone to court to try to stop the movie.

Prichard's memories of Agatha Christie are, not surprisingly, far more benign. He often visited Greenway, her home in Devon, where grandmother served as umpire for family cricket matches and each day at teatime read aloud from her mystery-in-progress. Guests would try to guess the villain.

Prichard, whose father was killed in World War II, went to Eton and Oxford, then hawked books for Penguin publishers to learn the trade. In 1967 he married Angela Maples, a secretarial school student he had met at Oxford.

He now spends two days a week working in London but otherwise lives with his family in elegant comfort at Pwllywrach (pronounced pull-tha-rah), a 500-acre, 18th-century estate in south Wales. The art-filled gray stone manor could be the perfect setting for Christie's multimurder Ten Little Indians, but inside the scene is cheerful. Alexandra Agatha, 9, James, 8, and Joanna, 6, romp with Telfer, the family's black retriever, a terrier named Piddles and three cats. Treasure, a pony, is stabled outside.

For the moment Prichard is weighing offers to turn Miss Marple into a TV series. "I think we've been through the violence and sex," he says. "If my grandmother's last books help contribute to family entertainment, nothing would please her better."