Heir Harry Potter spent November 1st, 1981; after his parents were killed, sequestered with Headmaster Albus Percival Wulfric Brian Dumbledore in Hogwarts School of Witchcraft and Wizardry. The toddler was poked, pricked, prodded, and tested by the Headmaster’s magic. The purported leader of the Light needed to know what happened to Voldemort, what exactly occurred between the child and the dark wizard. He used Occlumency on the toddler as well, but only got rudimentary feelings and the occasional distorted image that he preserved in a Pensieve. The wizard didn’t know to look and had no way to test for the favor of Death that runs in the Potter family through the Peverell line. He believed the child too young to have an organized mind. He believed the Greater Good worth the risk of hurting the young child to find out as much as possible from the only witness to the greatest even in a generation. He then tested for dark magic and found the Horcrux. The leader of the Light knew it could come in handy later since its existence meant the dark wizard would return. He left it intact but added it to a tracking gadget. He couldn’t risk anyone seeing the boy while he kept him under lock and key. Once his testing was completed, he used his personal time-turner to return Harry to Hagrid so he could be taken to his new home in the muggle world.
The headmaster had the bodies of Lord and Lady Potter brought to the infirmary at his school. He sealed the infirmary and set one of his secret gadgets to slow the passing of time compared to the outside world from the section. Since it’s November, he had to cast memory charms on the nurse and anyone in need of the infirmary while he had her test the bodies to see how they died and the magic signature on them. To distract from his actions, he leaked the information that Voldemort was killed by Harry Potter, himself calling the toddler The-Boy-Who-Lived. He knew now that the prophecy was for Harry Potter. A.P.W.B. Dumbledore was concerned with the Greater Good, not the small things like the child or his family.
Dumbledore is known to have gizmos and gadgets on his desk. What isn’t known is what they do or where he got them. Albus Dumbledore spent decades designing and perfecting the tools. Some effect time, some dampen magic, others negate the ability to heal at the same rate as wizards naturally do. A couple of his most-used items track and analyze Tom Riddle. His first gadget of this type was put together as quickly as possible when Tom was sixteen and the then Transfiguration professor suspected that his student opened the Chamber of Secrets. That tool was how the wizard knew a Horcrux was created using the death of Myrtle Warren. The next gadget of its type was designed to track Horcruxes with Tom Riddle’s magic signature. He never wanted to be caught unaware but didn’t plan to interfere with the hands of fate, as he reasoned it. He knew his plans couldn’t be motivated by pride because he was the only one left that knew and worked towards the Greater Good. His precious Gellert lost his way, but he still missed him and wished he hadn’t needed to make an example of him. That act broke something in the wizard., though his love persisted. Dumbledore visited Gellert every few years, but it hurt him to be reminded that he no longer had his partner to guide the people with. A.P.W.B. Dumbledore erroneously learned that he could only count on himself to do what was best for the Greater Good.