With Augusta Longbottom's survival, there was little that Dumbledore could do to Neville, and he, like Voldemort, believed that Harry was the real child of the prophecy. Still, Dumbledore did his damage there, using illegal Legilimancy on Frank and Alice to trap them in their own minds.
As soon as that was heard, Neville stood, his face suffused with fury; the expression matched by Augusta in her Wizengamot seat. Fortunately, Madam Bones anticipated this, and was already standing. "Shacklebolt, get to St. Mungo's immediately. Have their best Mind Healers see to the Longbottoms with this new information." Shacklebolt all but ran from the room. Neville nodded to Bones and then resumed his seat, still upset. Madam Longbottom did the same.
Once the courtroom had calmed, Madam Bones resumed her questioning of Dumbledore. He admitted to also using illegal Legilimancy on Augusta to make her harder on Neville, beating down his self esteem so that, if needed, he would sacrifice himself to Voldemort. He also stole several items, mostly books, from the Longbottom's house during the investigation into the attack.
Once the Potters were killed, and the Longbottoms incapacitated, many of Dumbledore's crimes against Harry really began. As the one who had cast the Fidelius charm, Dumbledore was aware of the second that it fell. He sent Hagrid to the house to look for survivors, before disillusioning himself and taking a portkey to the scene. By the time Hagrid had run to Hogsmeade, floo'd to Godric's Hollow, and found the ruins of the Potter house, Dumbledore had already collected everything of value. When Sirius Black arrived soon after Hagrid, and began to argue over who would take young Harry, Dumbledore hit him with the imperius curse and forced him to hunt down Pettigrew instead.
Having been a witness to their will, Dumbledore was well aware that Alice Longbottom was Harry's godmother. He also knew both that Sirius was Harry's godfather, and that he was innocent of betraying the Potters. However, as either godparent could interfere in his plans for young Harry, he used his position as Chief Warlock to send Sirius straight to Azkaban as soon as he was caught.
Dumbledore was also aware of the dozen other names listed in the will as suitable guardians for Harry, but none of them would do for his plans either. Thus, he kidnapped Harry to the Dursleys, where, in addition to casting illegal blood wards, he placed an imperius compulsion on Vernon Dursley, causing him to hate Harry. This, as Dumbledore explained, would cause Harry to grow up humble, and desperate to escape. Since he would know nothing of the wizarding world, he would view Dumbledore as his savior when eventually rescued from his relatives.
It also came out that Dumbledore was well aware of the horcrux in Harry's scar, as he obliviated Madam Pomfrey to its presence as soon as she found it. He also obliviated McGonagall several times over the past decade, whenever she enquired after the wellbeing of young Harry. Dumbledore admitted to being well aware of the abuse that Harry suffered, and the numerous incidents of self-healing, but waved them off as being necessary for his grand plan.
Once again the Veritaserum began to wear off, and as it was just past the start of lunch time, the Wizengamot agreed that Hogwarts would return Dumbledore to his cell while they took a break. Madam Bones ordered Augusta Longbottom, Madam Pomfrey, and Professor McGonagall to immediately take themselves to St. Mungo's Mind Healers. She also sent Auror Jones to inform Sirius' mind healers of the Imperius damage to his mind.
Harry immediately slipped from the room, unwilling to speak to anyone about what had just been revealed. Neville felt the same, so the other two heirs followed Harry, having a quiet lunch with their ghostly mentors in their private common room before returning for the second half of the questioning.
When he was again contained, dosed with truth serum, and revived, Dumbledore was questioned about his other actions regarding Harry and the school over the last ten years.
He admitted to using his positions as Supreme Mugwump and Chief Warlock to pass self-serving laws, seal the Potters' will, illegally claim guardianship of Harry, block the testing of experimental treatments on St. Mungo's patients that might have cured the Longbottoms, blocking legislation that would test muggleborns for connections to wizarding families, and several other scandalous bits of corruption that didn't directly relate to Harry.
Dumbledore also admitted to blocking and subsequently destroying all of Harry's mail, claiming a "guardianship stipend" from Harry's vaults every year, which went into his own pocket, and obliviating the Muggle child protection agencies who attempted to help Harry on almost a dozen occasions. He was also aware of the rampant abuse happening within Slytherin House, and, like Snape, allowed it to continue.
Finally, they reached the current year. Dumbledore confessed to colluding with Molly Weasley in return for her support in the Order. She had been sent to the Platform to find Harry and bring him onto the train, practically guaranteeing that Harry and her son Ronald would be best friends. Ronald had been given instructions by his mother to that effect, which Dumbledore intended to reinforce with legilimency once the boys were at Hogwarts. Once young Ginny Weasley began attending school and Harry showed any interest in girls, Dumbledore would provide the Weasleys with a love potion so that Ginny could one day marry Harry.
The presence of the Philosopher's Stone in Hogwarts, and the laughably easy set of traps leading to it were also revealed, along with Dumbledore's hope that the Stone would entice Voldemort to attack the school and that Harry would pass the test of the traps and stop him, possibly even fulfilling the Prophesy at last.
At the end of the very long questioning session, Harry was exhausted. He had known or suspected only some of Dumbledore's actions, but to hear them all laid out by the man, and to hear his reasoning… it made Harry sick.
Needing to be alone for the brief break before dinner, and knowing that the other two would know where he was going, Harry hurried outside. Once he had become acquainted with the new thestral herd, he mounted one particularly eager stallion and away they ran, zooming above the grounds as fast as his wings could take them.