A scream from an empty apartment

This happened to me a few months ago. Our neighbors upstairs are a wonderful couple, Natalia and Viktor, with two children: a son named Antoshka and a daughter named Lyuba. Anton is only one year old, and Lyuba is already five. She's sweet, smart, and always laughs a lot. They moved into this apartment recently, but all the neighbors have already grown fond of them.

One day, they all went to their dacha. I saw them load everything into the car and turn the corner. The apartment was empty. I was home alone that day, so I sat and watched TV until late. Suddenly, I heard a terrible, inhuman scream from the apartment above. I was wary—there was no one else in the apartment. If Natalia and her husband had returned, I would have heard it, but until then, everything had been quiet. We have very good soundproofing.

After sitting for a while, I almost thought I imagined it, but then the scream repeated itself. I was already scared. It was around midnight. I left the apartment, went up to the neighbors' door, and started listening. When the screaming started again, I didn't hesitate to call the police. While I was waiting, a couple more people crawled out of their apartments. It turned out I wasn't the only one who had heard the screams.

When the police arrived, no one opened the door. There were only two officers, but as soon as they heard the screams, they immediately called a team and started breaking down the door. It resisted for a long time, as if it had been locked not only from the outside but also from the inside. And screams kept coming from inside the apartment. Finally, the door opened. All of us standing in the stairwell were met with a horrific scene: a little girl covered in blood and bruises, lying curled up in the hallway, and only her light-brown braids, stained with blood, let us know it was Lyuba. As soon as the ambulance arrived, the girl was immediately taken to the hospital. 

Soon, Natalya, Viktor, and their son rushed in. Their eyes were wide, Natalya was in tears, and both were terrified. They were panicked, because their little daughter had gone with them, but according to the parents, when they arrived at the dacha, Lyuba ran into the house and disappeared. They searched for her for a long time, screaming for her, and then the neighbors called: "Come over, your daughter is home..."

Some time passed, Lyuba was recovering, but she had no memory of what had happened to her in the apartment. Her mother spent days sitting by her daughter's bedside in the hospital. The strangest thing is that no trace of strangers was found in the apartment. A frightening mysticism surrounds this whole story. Natalya, Viktor, and the children have now moved to another apartment, and I have never seen them again.