Who killed Markiplier?

Curiouser and curiouser

You stepped to the doors, pushing one of them open. Mark's room was a mess. The walls where a dark turquoise, the carpet was tan just like everywhere else in the house. Sheets and pillows where flung everywhere, even over the dresser and the floor. Mark's king sized bed was unmade, seems the Butler hasn't been here. A tired sigh came to your left, "Looks rough, but I don't think he was killed here." The Detective spoke. And it looks like no one else was in the room where it happened. "Take a look around, see if you find anything, but be careful!" He jabbed a finger at you. "I've lost 3 partners before to bedroom boobytraps." The Detective walked over the other other side of the room, you looked more closely at the mess. A book, a envelope and a black lace veil-looking cloth laid on a small headboard. As you carefully stepped over the trash the Detective voice called "Make sure you don't tamper with any evidence!" You moved to a corner, which was shaped strangely from the rest of the room. A light round wooden table sat in the middle of two chairs, there were photos on the table. Apon a closer look, you saw that the first picture was of the Mayor, Mark and the Colonel. Looking happy and smiling, the next photo was different. It was the Mayor, Colonel, Mark and a woman. The woman and Mark were smiling while Damien and the Colonel where stone faced.The third photo was Mark and the Mayor, the glare from the windows made it hard to read their expressions. There was one more photo lying face down, "Lemme know if you find anything." The Detective spoke again, you picked up the jet black frame and turned around to the Detective. You showed him the picture, "You find a clue?" He asked. You turned the picture over so that you could see. It was the Colonel, alone. Some of the glass was shattered. Why was it broken? And why did Mark have this in his room? As you tore the picture of the Colonel away, the real Colonel jumped in his place. Almost in the same outline of the photo. After almost giving you another heart attack the Colonel spoke,"You're quiet on the case, aren't you?" He said. The Detective shot his head up, "Say, Detective, may I borrow your friend here?" The Colonel asked, his hands on his hips. His back was to the Detective, "Yeah, sure. Don't worry partner, I'll handle it from here." He said, holding up some kind of red cloth. "Bully..." The Colonel turned, "Take a walk with me, I thought it was about time that we got to know each other."