Was there other evidence supporting Black's conviction? How did they come to the decision to send him to Azkaban?
- There was apparently a street full of Muggle witnesses who "saw" Pettigrew get murdered.
- Dumbledore and Lupin were aware that Sirius was the Potter's Secret-keeper, but not that they had secretly switched to Peter. As far as they were concerned, there was only one person who was capable of betraying the Potter's location.
- Keep in mind, everyone who knew them knew that Sirius was the competent, rebellious one and Peter was an incompetent loser. Sirius also came from a long line of Slytherins and had multiple family members who supported Voldemort. He was a much better profile for the traitor than Peter.
- Sirius didn't help things by laughing maniacally when he was taken into custody.
According to Sirius, Barty Crouch threw him into Azkaban without a trial. Now Dumbledore contradicts this by saying that he gave evidence at Sirius' trial, so we don't know exactly how much evidence was required to throw him away. But even if Sirius had given his side of the story, it would have sounded far-fetched. The reader can only be sure it's true because Sirius physically produces Peter Pettigrew.
Killing peter pettigrew did not send sirius to azkaban , The fact that peter blew up half the street killing twelve muggles it what sent sirius to azkaban. peter shot a curse behind himself right before sirius fired a curse at peter so the witnesses see sirius attempt to kill peter, the street blow up , body parts everywhere, and just the finger left of peter Followed with sirius admittance that he did kill peter as he thought he did. Sirius then sat in jail peacefully knowing he had avenged the potters until the day he saw fudges newspaper and saw Ron and Peter on the front page. In cases of mass murder with multiple witnesses, and an admittance of guild you do not need a trial.