sentences:  Mortimer found a close ally in Nils Granlund, who managed WHN radio and broadcast live jazz performances from NYC nightclubs, and by 1939, Mortimer had his own radio program on WMCA, a station owned by Flamm.Mortimer made appearances regularly at Granlund-staged events, and eventually produced Granlund-style dance revues for New York City nightclubs.Mortimer served as a first lieutenant in the Signal Corps from 1942 to 1943, then returned to New York City and began a collaboration with Jack Lait that produced several bestselling crime books.