I think the killer is Minty Fresh! Here's how I know why:
The first kill of this spree! Great... So, I think once Fancy Guy joined Minty, it was pure murder, as nobody watched, due to everybody either in the mansion or on the race track, it was the perfect opportunity for Minty to murder Fancy Guy! Minty first drowned Fancy Guy, leaving his lifeless body floating in the pool. He then sawed one of Fancy Guy's arms off, and also sawed his body in half, and if the drowning didn't kill him, the loss of blood sure would have! After the murder, Minty got out of the pool, dried off, and disposed of the half of an arm and half of a body along with the saw in a secret area only he could get to.
That was this murder, all wrapped into one response.
Yet again, I think Minty Fresh is the killer! Here's why:
Obviously, me and him are the prime suspects, as we were in the movie theater for a while, obviously with some popcorn.
But when Turquoise told Tan to move out of the way, and he didn't listen, Minty poisoned his popcorn while Turquoise wasn't looking, and gave some to Tan to lure him away from the screen. Soon after, when the movie was over, Minty and Turquoise left, and Minty had a homicidal gleam in his eyes.
The next day, Tan vomits and dies from the poison.
Minty has been the prime suspect for two cases now. Is he hiding something from us?
The killer is CUDDLES! Here's how I know why this time!:
Aah, cute, innocent Cuddles. Always being a bystander to the cases.
Staying outside in Case 1, Being in the movie theater when Tan got poisoned in Case 2, and lastly, sitting right next to the victim in Case 3.
Here's how Cuddles' third murder played out:
So, with two dead, Cuddles wanted more to die. Of course, only he knew of the ways to kill them, as he was smarter than he looked.
He walked in on EC and Yellow to help make the ice cream for the next day. But, while EC and Yellow's backs were turned and they were focused on the ice cream, Cuddles decided on two setbacks, only one lethal setback though.
He put exploding flour on one specific cherry, and he also put ground-up nausea pills inside a completed sundae, obviously, not more than three.
With his trap set, the next day rolled around.
Once everybody sat down, he put the nausea-pill sundae at a random spot, so that only that one person would complain of the nausea. That so happened to be Sky.
But Cuddles' third target was not Sky, but it was Frisk. He wanted revenge for Frisk beating him up the previous day, so he gave a normal sundae to Frisk.
When Frisk asked for a cherry on his sundae, as everybody else's sundaes each had a cherry, Electric Cyan grabbed the only cherry left: The one with the exploding flour. When Cuddles took it away from her, EC thought nothing of it, until Frisk exploded, sending his limbs off his body. Obviously, Frisk ate his cherry first, not even touching the sundae. But then, he exploded. His life was over.
If these murders were the work of you, I will put an end to you.
I swear to do this, CUDDLES!
I know you guys would suspect me for this fourth murder, but I have a different guess on our 4th killer.
I think it is Cy-Blu. Here's why:
Cy-Blu decides to follow-up on Cuddles' three murders, all with different ways to die. Today, Cy-Blu added to that list with a different way to die.
With the sudden toss of Titanium Tile, which went straight into the nauseas character from Case 3, Sky, TT ran off, no apology, no turning back.
But when Cy-Blu said he was "Practicing his throw", it only made him even more suspicious. That was an excuse to get out of a tricky situation for the fourth murder.
When night fell, CB went to TT's room first, knocked him out, then dragged him to the kitchen, and poured acid on his head. TT's screams echoed throughout the mansion, while CB laughed to himself while heading back to his room as fast as he could. He was in such a hurry that he left the bucket to hold the acid in the kitchen, next to the body.