How did Sirius get into prison?

Pettigrew betrayed Harry's parents. Sirius caught Pettigrew, but Pettigrew managed to escape. He blew up a muggle in a street and pretended to be dead, which was his only achievement that was not covered up by Sirius. Sirius (even his best friend thinks he is a secret, and he is the only one who can betray Mr. and Mrs. Zhan Mu) was arrested for murder and stayed in Azkaban for 12 years. Everyone thinks he is a traitor and a servant of Voldemort. Peter screamed that Sirius Black killed Zhan Mu and Lily and then made a huge explosion. Sirius Black was identified as the murderer of the Potters and was sent directly to Azkaban without trial.