who murdered Scarpia?

Answer 1

In Act III

A shepherd sings below, and as dawn approaches Cavaradossi is brought in before the jailer. Cavaradossi tries to write a last letter to Tosca, but loses himself in memories of her. Tosca appears, and tells Cavaradossi how she killed Scarpia, and how there is to be a mock execution. The lovers plan their departure, and their voices join in a duet which ends on a note less of love than of defiance. But Scarpia has kept one last card up his sleeve. The mock execution was real after all, and Cavaradossi falls dead. Meanwhile, Scarpia’s body has been found. Spoletta and Sciarrone dash in to arrest Tosca, but she eludes both of them and plunges to her death over the parapet.