Sirius Black was imprisoned in Azkaban for twelve years without a trial because he was believed to have betrayed James and Lily Potter to Lord Voldemort and murdered twelve Muggles along with his former friend, Peter Pettigrew. In the aftermath of the Potters' deaths, the Wizarding World found Sirius laughing hysterically in a street destroyed by a massive explosion, with only a severed finger of Pettigrew remaining. The public and the Ministry of Magic, led by Barty Crouch Sr., assumed Sirius was the Potters' "Secret Keeper" and that he had turned "Death Eater." In reality, Sirius had convinced the Potters to switch Secret Keepers to Pettigrew at the last minute, thinking Voldemort would never suspect the "weak" Pettigrew. Pettigrew was the true traitor who framed Sirius by blowing up the street and transforming into his Animagus form (a rat) to escape. Because the switch was a secret known only to the two of them, and because eyewitnesses saw the confrontation, the evidence was overwhelmingly against Sirius. His lack of a trial was a result of the Ministry's desperate desire to show "decisive action" during the height of the Dark Lord's reign of terror.