Author's Note: A note as to my own personal fanon: I take everyone's fear of Voldemort's name, in light of Deathly Hallows, as a sign that the Taboo was active during the first war as well. Hence any snippets set during or immediately after the first war will have everyone except Dumbledore avoiding the name.
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"You don't understand - you're making a mistake."
"About what, Black?" Auror Brown sneered. "You confessed, didn't you?"
The haggard man looked up at his guards. "I - I wasn't thinking." He swallowed hard. "It is my fault James and Lily are dead - but I didn't betray them. I wasn't the Secret-Keeper."
"Can you prove it?"
Black instantly crossed an arm over his heart. "By Merlin and my magic, I swear that I was not James and Lily Potter's Secret-Keeper." The Aurors blinked as a surge of magic went through them, and he extended a hand. "Please - let me show I still have magic-"
Auror Brown's partner, Auror Patil, tossed him a toy wand they had been issued to check the validity of Wizard's Oaths. Both of them held him at wandpoint as Black held it up; he muttered, "Lumos," and it immediately lit.
There was a pause. "Then who was?" Auror Brown demanded.
"By Merlin and my magic, I swear that - to the best of my knowledge - Peter Pettigrew was the Secret-Keeper of James and Lily Potter." Another jolt of magic, and still the toy wand pulsed with light.
"That's why you killed him, then?" Auror Brown shook his head. "For betraying them?" He sighed and passed a hand over his eyes. This was a bad business. "There's still the matter of those Muggles-"
"By Merlin and my magic, I swear that it was Peter Pettigrew's spell, which he shot behind him to make it look as though it had come from me, that blew up the road and murdered those poor Muggles." The wand did not dim.
"And he blew up himself in the process?" Auror Patil questioned. Black gave them a sick and angry smile.
"By Merlin and my magic, I swear that Peter Pettigrew was an unregistered rat Animagus." The light remained unchanged. Auror Brown swore under his breath; Black looked up at him wanly. "Oh, and by the way, if all you found was a finger..." He saw the look on Auror Brown's face, and a weak and bitter smile tugged at his lips. "Yeah, he cut that off beforehand. I - paused for a moment, because I couldn't figure out what he was doing. Then he blew up the street."
"Would anyone have told him we only found the finger?" Auror Patil asked. Auror Brown shook his head.
"You knew he was an unregistered Animagus, and told no one?" Auror Brown demanded. "That in and of itself is an offense-"
"Would you have given information to the Ministry, knowing the place was crawling with You-Know-Who's infiltrators?" Black demanded. "He used his Animagus form to spy for us during the war! Wormy was one of our most valuable-" He shuddered, and curled in on himself.
"Wormy?" Auror Patil questioned.
"Wormtail," Black said, as though the mere name was tainted with poison. "His nickname. You know, for his Animagus form - don't rats' tails look like worms to you? Those little, naked pink things?"
"Did you know of any other unregistered Animagi, Mr. Black?" asked Auror Brown.
Black gave a choked laugh. "Are your regulators going to harass a dead man?"
"James Potter was an Animagus?"
"By Merlin and my magic, I swear that James Potter was an unregistered stag Animagus," Black declared, and the toy wand remained undimmed.
"I suspect the rest of your little group were as well?" Auror Patil asked, but Auror Brown shook his head.
"No, Lupin's a registered werewolf."
"I'll beat you to it, since I'll bet you'll try to make me swear a Wizard's Oath about it anyway. By Merlin and my magic, I swear that I am an unregistered dog Animagus."
Auror Brown was starting to feel worn out. These were more Wizard's Oaths than he'd ever seen sworn in quick succession, and he'd attended some of Mr. Crouch's recent interrogations. "Are those all of them, Mr. Black?"
"By Merlin and my magic, I swear that I know of no other unregistered Animagi."
"So you and all your friends were Animagi - except the werewolf - and Peter Pettigrew, who was secretly the Potters' Secret-Keeper and betrayed them to He-Who-Must-Not-Be-Named, used his rat Animagus form to escape when you confronted him, cutting off his own finger and murdering a dozen Muggles to cover his own flight. Is that correct?"
Black nodded. "Do I have to take a Wizard's Oath for that whole sentence?"
"No, I think you've proven yourself," Auror Patil said with a sigh. He shook his head. "One final question, Mr. Black. Would you be willing to swear a Wizard's Oath that you have never willingly served He-Who-Must-Not-Be-Named, nor knowingly and willingly aided any of his servants?"
Black opened his mouth, then closed it. "Er - my brother Regulus became a fan of You-Know-Who at a young age. I don't know how, or when he began actively serving him, but -" He shook his head. "Last time I aided him - Regulus, I mean - on anything, he was fifteen and needed advice on some of his Arithmancy homework. Would that violate the oath, if he was already serving You-Know-Who by then? I don't know - I think he joined only after coming of age, but you know my family's reputation - I can't be sure -"
"I believe that would be covered under 'knowingly'," replied Auror Patil. "Aside from that, are you clear of any possible collaboration with He-Who-Must-Not-Be-Named's servants?" Black nodded furiously. "Then swear."
"By Merlin and my magic, I swear that I have never willingly served He-Who-Must-Not-Be-Named, nor knowingly and willingly aided any of his servants."
The toy wand did not go out until Auror Patil accepted it from Black's hands. "Mr. Black, on behalf of the Ministry, I would like to offer an apology," Auror Brown said. "This has been a terrible misunderstanding-"
"It was my fault, though." Black stared hollowly at the wall. "It is all my fault. If only I'd pushed harder to remain Secret-Keeper - if only my damned family wasn't on You-Know-Who's side - it's why we didn't use me, we were all afraid they'd use blood magic to somehow force it out of me - if only we hadn't doubted Remus - none of us knew much about werewolf pack structures, we were afraid Greyback could somehow use the bond to force him -" A sob broke from him. "And then Peter sold us all out like the damned rat he was." He buried his face in his hands. "It is all my fault. It is. I good as killed James and Lily- I did-"
As Black howled into his hands, Auror Patil glanced at Auror Brown. "The bond? Do you know?"
"Lupin's a Greyback infectee," Auror Brown said, and his partner sucked in a breath. "There have been rumors Greyback has some sort of control over some of his victims. No one knows if it's magical or psychological, however; he usually dragged them with him if their parents weren't nearby, and they were already..." He tapped his head. "...damaged by the time they were recovered."
"I see," Auror Patil said grimly. He looked at Black, who had retreated once more into his own little world of grief. "This could have been a disaster for all involved. A Death Eater on the loose with such a conveniently ubiquitous creature for his Animagus form, one suited to getting places larger animals couldn't reach..." He shook his head. "I can't even imagine what havoc he might have wreaked as a 'dead man'." He turned back to his partner. "We have to put everyone on high alert. A week from now, we could be called in to find he's holding the Minister hostage."
"I know the Ministry's in disarray, but don't you think people would notice a rat running down the halls?"
"If he had a human's intellect and wit enough to hide? Or adopted other methods - he might Imperius someone to carry him in a suitcase."
Auror Brown blanched. "Good Merlin." He looked down at Black. "Do you have any idea when Pettigrew turned traitor?"
"Do you think we would have trusted him if we did?" Black screamed, and the two Aurors flinched back; the despair in his voice reminded them of the survivors of Death Eater raids, and they both silently marked him down as a potential suicide risk. Then Black swallowed, and he gave a slow, painful nod. "We knew there was a spy," he whispered. "The McKinnons' hiding place was betrayed - it's why we resorted to the Fidelius - and Fabian and Gideon were ambushed at their workshop - only Order members knew where it was. It's why we worried about Remus - we knew he never would have betrayed us, if he had a choice, but we thought maybe it was being pulled from his mind -" He was shaking his head. "We never suspected Peter. Never." He looked at them, his face pale and drawn, and then lowered his eyes. "The past year," he said so quietly that they could barely make him out. "At least."
"There have been a few strange cases..." Auror Patil said slowly. "The murder of Edward Bones and his wife... the protections upon their house were believed to be flawless, but further inspection showed someone had forced open the smallest of gaps in the shield... but the thing that made no sense was that it could never have fit a human - it was barely the size of a man's fist - and yet they had clearly been murdered by a wizard... But no known wizard had an Animagus form that could pass through a hole of such small-"
"No," Black croaked. "No."
But his inner answer was clearly yes, for he buried his head between his knees and began to cry.
"This is a bad business," Auror Brown said quietly.
"You stay with him," Auror Patil said softly, nodding to Black. "I need to inform Mr. Crouch of all of this immediately. I believe I can seek clemency for his concealment of his and his friends' Animagus forms on the grounds of keeping intelligence in wartime from the enemy, but Mr. Crouch urgently needs to know that Black is innocent, and that a rat Animagus with no aversion to deception, betrayal, and murder is roaming England." He turned to leave, then glanced at his partner again. "Ironically, I think Black, as an innocent man, needs more guards than when he was thought guilty. Pettigrew full well intended to have Black either die resisting arrest, be Kissed in short order, or receive life in Azkaban. If he learns we have no plans to dispose of him, he may well act to finish the job himself."