The blood stained Egima part-1

Chapter 1...Around 8 o'clock in the night, a detective receives a call. A nervous man on the call says, "Hello sir, there's been a big problem here, please come to our village quickly." The detective promptly arrives at the location. The village is called Oakwood. Upon arrival, he notices that all the villagers are gathered outside. The detective calls the man again and reaches his location. There was a decent crowd there too, but the detective's attention is drawn to a boy and two men.The detective asks them, "Did you call me?" One man replies, "Yes, I made the call." The detective asks, "Alright, tell me what happened that you need a detective; why didn't you inform the police?" The man replies, "We don't want to involve the police in this matter; maybe the police aren't needed here." The detective puts aside his response and asks directly, "Tell me straight, why did you call me here?" The man says, "My name is John, I'm a businessman. I've been away for a few days on business. My daughter stayed here to attend her college classes. When I returned, I found out that my daughter has been missing for a few days, and all the doors and windows of the house are locked; we can't even go inside."Upon hearing this, the detective enters the house and notices that the door is broken. He enters further and notices a smell. Ignoring it, he starts searching the house. In some places, the detective notices blood, but he ignores it too and enters John's daughter's room, where he again notices a foul smell but dismisses it, thinking, "Such a foul smell, maybe a rat or a cat died." With this thought, the detective enters Lisa's room. There too, he conducts an investigation, but everything seems normal. The detective learns that John's daughter's name is Lisa. The detective checks Lisa's computer, and everything seems normal there too. After that, the detective starts reading all of Lisa's emails...Olive: "So friends, any plans? Shall we go somewhere?"Sarah: "Yes, yes, shall we go somewhere this weekend?"Rook: "Hey, let's go hiking somewhere, it'll be fun."Rose: "But where will we go hiking?"Lisa: "Whitney Mountain, how does that sound?"Sarah: "Okay, done. We'll all go to Whitney Mountain, and Rook, tell Zayn about this, alright?"Rook: "Yes, yes, I'll tell him."Lisa: "Eren?"Olive: "He won't come."Rook: "Okay friends, get ready for hiking tomorrow, we're all going."... After reading all this, the detective realizes everything seems normal. He also reads Lisa's other chats, where it's evident she mostly conversed with Eren. Reading their chats confirms to the detective that they were in a relationship. Taking note of all this, the detective notices many rats coming out of the basement. As he approaches the basement door, he smells something foul. After a bit of hesitation, the detective opens the basement door and is completely shocked to find six dead bodies in a terrible state. Seeing this sight, the detective starts feeling sick and rushes out to inform the police. A few days later, the post-mortem reports of all of them come in. The detective starts checking all the reports and is shocked to find out that all the dead bodies belonged to Lisa and all her friends.Some time later, the detective visits John and sees him somewhat upset. Seeing Lisa's dad devastated, the detective asks him, "Did you know where Lisa was going this weekend?" John replies, "No, I thought she was attending college, so I left her here." Upon hearing this, the detective leaves and thinks to himself, "I don't know why, but I feel... No, it can't be, a father wouldn't do such a thing to his daughter." The scenario changes, and we see the detective outside Eren's house...