Sirius was arrested, accused of murdering Pettigrew and the muggles and of serving Voldemort, and was promptly thrown in prison by Barty Crouch, Sr. without receiving a trial. He spent the next twelve years in Azkaban, brooding over his friends' deaths and obsessing over Pettigrew's betrayal.
Sirius blames himself for the deaths of James and Lily.
It's common for people to experience misplaced guilt after the death of a loved one, and Sirius is no exception. When we first meet Sirius in Prisoner of Azkaban, his grief has been stunted by his time in prison.
The answer is that Sirius wanted to deflect attention from the real Secret-Keeper. He probably hoped Voldemort would go after him so he could steer attention away from Pettigrew.
This massacre in London occurred on 1 November 1981 when Peter Pettigrew killed twelve Muggles with an extremely powerful explosive curse (possibly the Blasting Curse), leading to the false conviction and imprisonment of Sirius Black.
Thus, Sirius Black is the very image of a tragic Greek hero, He was born to a noble family, one he later feuded against. He found a new family but sadly lost them through a grievous betrayal. In a fit of reckless loyalty, he pursued the traitor, but failed to catch him, and was banished to the Underworld.
Sirius's intense love for James, his grief after James's death, and his anger towards Peter drove him to insanity, getting him locked up in Azkaban for crimes he never committed.
During The Purity War, Sirius Black was a member of The Order of The Phoenix and gave a confession to being a member of The Death Eaters, and betraying the Potters to The Dark Lady, admitting to putting the Imperius Curse on dozens of other Death Eaters. For his crimes, he was sentenced to Life in Azkaban Prison.
It is hinted that he has done something that would inspire Harry to seek revenge, but it is not until Christmas that Harry learns that Sirius betrayed Harry's parents to Voldemort, then, when confronted by their friend Peter Pettigrew, killed Pettigrew and twelve incidental Muggles.
Sirius Black proved his innocence by revealing (with the assistance of Professor Lupin) Wormtail's presence in the guise of Scabbers the rat, and telling his story of the switch in the secret-keeper and the duel in the street.
Because he didn't realise people would think he was guilty. He turns up, tries to take Harry, Hagrid says no, then Sirius buggers off to find Peter, unaware that Dumbledore is about to sell him down the river and give him a staring role in “12 years a slave” (metaphorically speaking).
Dumbledore seemed to have very little personal affection for Sirius and although he showed some grief after his death, it was mostly because he felt guilty and sympathy for Harry.
Bellatrix isn't sad about killing Sirius. She taunts Harry about it. Far from showing remorse for killing Sirius, she next stalks her niece, Nymphadora Tonks. The only relative for whom she shows any affection is her sister Narcissa.
Upon looking into Dumbledore's manipulative ways and his intense plans, the most likely reason Dumbledore did not help Sirius is that the result would have interfered with his plans for Harry. Had Sirius not been sent to Azkaban, he would have been Harry's legal guardian instead of the Dursleys.
90% here thinks he laughed because he simply lost it, he had a mental breakdown. Though some people believe Wormtail put a laughing charm on him after he blew up the street to make him laugh uncontrollably.
No one knows the truth about Sirius Black yet, not even Severus Snape. At that time, he didn't know that Sirius Black was innocent. At that time, he knew what everyone else thought they knew - that Sirius was a dangerous criminal that was out to get Harry Potter and that was said to be Voldemort's right-hand.
In the film, Bellatrix hit Sirius with the Killing Curse, Avada Kedavra, killing him before he passes through the Veil. In the book, the curse that hits Sirius is not identified, and his being knocked through the Veil is what causes his death.
The short and simple answer to your question is “no”. Dumbledore - like the rest of the wizarding world - did not know that Peter Pettigrew set up Sirius to take the fall for his crimes.
Why did Lupin believe for so long that Sirius was the traitor who betrayed the Potters to Voldemort? Because he didn't know that they had changed their Secret Keeper. Why didn't he know? The group suspected that there was a spy in their midst, and both men believed that it may have been the other.
The story of Sirius Black and Marlene McKinnon first began in their sixth year at Hogwarts. She was new and he was more than happy to make her feel welcome.
As the daughter of Sirius Black, Aurora has a big legacy, one she doesn't want to carry. Half the Wizarding World call her father a Blood Traitor and the rest call him a Death Eater. She is forever judged by her father and by her name.
Alphard Black
Kudos to Alphard for being one figure in Sirius's life who actually supported him.
Harry blames Dumbledore for Sirius' death and rages at the Headmaster in his office following the battle at the Ministry.
Sirius was arrested, accused of murdering Pettigrew and the muggles and of serving Voldemort, and was promptly thrown in prison by Barty Crouch, Sr. without receiving a trial. He spent the next twelve years in Azkaban, brooding over his friends' deaths and obsessing over Pettigrew's betrayal.
Sirius Black didn't want to kill Harry Potter. He wanted to kill Peter Pettigrew (Wormtail) aka Ron's rat, Scabbers. ... Sirius, being their loyal and best friend wanted to take a revenge.
Sirius Black (born November 3, 1959 - died June 18, 1996, aged 36), also known by his nickname Padfoot, is a major character from the Harry Potter series.