Christie's reputation as "The Queen of Crime" was built upon the large number of classic motifs that she introduced, or for which she provided the most famous example. Christie built these tropes into what is now considered classic mystery structure: a murder is committed, there are multiple suspects who are all concealing secrets, and the detective gradually uncovers these secrets over the course of the story, discovering the most shocking twists towards the end. Culprits in Christie's mysteries have included children, policemen, narrators, already deceased individuals, and sometimes comprise no known suspects (And Then There Were None) or all of the suspects (Murder on the Orient Express).