Algodoo

Yuri and the culprit met on day 1 and she shipped the culprit which they didn't like.
Looking for revenge and scared that they may die, the culprit looked around on how to murder Yuri without seeing blood. After seeing the gym and the box with sweat shirt and pants, the culprit thought of this plan. The culprit took the box with the clothing to the gym and told Yuri to meet them at the gym to excersize to get happy or off her mind. When she was putting on her clothes, the culprit tied the ropes on her sweatshirt to the treadmill. The culprit then turned the treadmill to the fastest mode which suffocated Yuri. After hearing the four people, they didn't have much time to get away so they just left. There's only one person who would think on tying the cords to the treadmill and that's Michalina.
I will be AK-666 unless Avaughn Wood is availlible.

Since I must, I shall.

Here's all that happened.

First, the killer was invited to Yuri's room by Yuri, obviously.
Yuri wanted to talk with the killer about shipping them with a certain person.
The killer only wanted to be friends with that certain person, and they were steamed.
The killer knew what to do. They took Yuri's shirt cord and strangled her with it.
She was pleading for her life.
The killer didn't give in, and then Yuri was dead.
The killer then privately moved Yuri's body to the workout room and tied her shirt cord to a treadmill, and then they started the treadmill.
That's how it all played out.
Got anything to say, Drew? This is how your murder was constructed.

Very short and sweet for this case.

I think that It was Kino because he was the last person to check out the Treadmill in the gym. I really don't know to be honest. This is all of the information that I have but at least it's something.