Barty Crouch Junior

"My mother saved me. She knew she was dying. She persuaded my father to rescue me as a last favor to her. He loved her as he had never loved me. He agreed. They came to visit me. They gave me a draft of Polyjuice Potion containing one of my mother's hairs. She took a draft of Polyjuice Potion containing one of my hairs. We took on each other's appearance. My mother died a short while afterward in Azkaban. She was careful to drink Polyjuice Potion until the end. She was buried under my name and bearing my appearance. Everyone believed her to be me."
"And what did your father do with you, when he had got you home?" said Dumbledore quietly.
"Staged my mother's death. A quiet, private funeral. That grave is empty. The house-elf nursed me back to health. Then I had to be concealed. I had to be controlled. My father had to use a number of spells to subdue me. When I had recovered my strength, I thought only of finding my master... of returning to his service."
"How did your father subdue you?" said Dumbledore.
"The Imperius Curse," Moody said. "I was under my fathers control. I was forced to wear an Invisibility Cloak day and night. I was always with the house-elf. She was my keeper and caretaker. She pitied me. She persuaded my father to give me occasional treats. Rewards for my good behavior."

"Did anybody ever discover that you were still alive?" said Dumbledore softly. "Did anyone know except your father and the house-elf?"
"Yes," said Crouch, his eyelids flickering again.
"A witch in my father's office. Bertha Jorkins. She came to the house with papers for my father's signature. He was not at home. Winky showed her inside and returned to the kitchen, to me. But Bertha Jorkins heard Winky talking to me. She came to investigate. She heard enough to guess who was hiding under the Invisibility Cloak.
My father arrived home. She confronted him. He put a very powerful Memory Charm on her to make her forget what she'd found out. Too powerful. He said it damaged her memory permanently."

"Tell me about the Quidditch World Cup," said Dumbledore.
"Winky talked my father into it," said Crouch, still in the same monotonous voice. "She spent months persuading him. I had not left the house for years. I had loved Quidditch. Let him go, she said. He will be in his Invisibility Cloak. He can watch. Let him smell fresh air for once. She said my mother would have wanted it. She told my father that my mother had died to give me freedom. She had not saved me for a life of imprisonment. He agreed in the end.
"But Winky didn't know that I was growing stronger. I was starting to fight my father's Imperius Curse. There were times when I was almost myself again. There were brief periods when I seemed outside his control. It happened, there, in the Top Box. It was like waking from a deep sleep. I found myself out in public, in the middle of the match, and I saw, in front of me, a wand sticking out of a boys
pocket. I had not been allowed a wand since before Azkaban. I stole it. Winky didn't know. Winky is frightened of heights. She had her face hidden."
.
.
I wanted to attack them for their disloyalty to my master. My father had left the tent; he had gone to free the Muggles. Winky was afraid to see me so angry. She used her own brand of magic to bind me to her. She pulled me from the tent, pulled me into the forest, away from the Death Eaters. I tried to hold her back. I wanted to return to the campsite. I wanted to show those Death Eaters what loyalty to the Dark Lord meant, and to punish them for their lack of it. I used the stolen wand to cast the Dark Mark
into the sky.
.
"When Winky was discovered, my father knew I must be nearby. He searched the bushes where she had been found and felt me lying there. He waited until the other Ministry members had left the forest. He put me back under the Imperius Curse and took me home. He dismissed Winky. She had failed him. She had let me acquire a wand. She had almost let me escape."
.
.
"Now it was just Father and I, alone in the house. And then... and then... My master came for me.
"He arrived at our house late one night in the arms of his servant Wormtail. My master had found out that I was still alive. He had captured Bertha Jorkins in Albania. He had tortured her. She told him a great deal. She told him about the Triwizard Tournament. She told him the old Auror, Moody, was going to teach at Hogwarts. He tortured her until he broke through the Memory Charm my father had placed upon her. She told him I had escaped from Azkaban. She told him my father kept me imprisoned to prevent me from seeking my master. And so my master knew that I was still his faithful servant, My master conceived a plan, based upon the information Bertha had given him.
He needed me. He arrived at our house near midnight. My father answered the door. It was very quick. My father was placed under the Imperius Curse by my master. Now my father was the one imprisoned, controlled. My master forced him to go about his business as usual, to act as though nothing was wrong. And I was released. I awoke. I was myself again, alive as I hadn't been in years.

"And what became of Wormtail after you attacked Moody?" said Dumbledore.
"Wormtail returned to care for my master, in my father's house, and to keep watch over my father."
"But your father escaped," said Dumbledore.
"Yes. After a while he began to fight the Imperius Curse just as I had done. There were periods when he knew what was happening. My master decided it was no longer safe for my father to leave the house. He forced him to send letters to the Ministry instead. He made him write and say he was ill. But Wormtail neglected his duty. He was not watchful enough. My father escaped. My master guessed that
he was heading for Hogwarts. My father was going to tell Dumbledore everything, to confess. He was going to admit that he had smuggled me from Azkaban.

~Veritaserum