Agatha Christie was a playwright.
Dame Agatha Mary Clarissa Christie , Lady Mallowan , DBE ( née Miller ; 15 September 1890 -- 12 January 1976 ) was an English crime novelist , short story writer and playwright . She also wrote the world 's longest-running play , a murder mystery , The Mousetrap , and six romances under the name Mary Westmacott . Christie 's stage play The Mousetrap holds the world record for longest initial run . Later the same year , Witness for the Prosecution received an Edgar Award by the MWA for Best Play .