Well, it doesn't seem to many people are too interested in playing. Maybe some extra evidence will help. Maybe it won't. But at any rate I cannot post the murder solution until somebody solves it. This case can only be solved by asking questions, searching rooms, and making accusations.
The evidence below is a few extra events that also occured during the evening. You must fit them into the story that's already been posted according to the time.
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KITCHEN-6:55 PM
The first thing that caught Miss Scarlet's eye when she entered the Kitchen was a bottle of poison standing presently upright on the table.
"Hmmmmm, quite lovely," She thought,
"But...no....it may be too late for that."
Then her eye turned to something else.....
"Oh my!" She declared.
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STUDY-6:57 PM
"Ann, you know what?" Plum spoke, "I've finally decided I'm going to do something about this stupid аss who thinks he can pout at me for beating him at his sorry little...game."
Madame Rose remained solemn and quietly, she said him.
"Nate, be very quiet...and take this with you."

Just then, Plum felt the cold smooth steel of a silver Pistol being placed into his hands....
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SCARLET'S ROOM-7:06 PM
KNOCK! KNOCK!"Are you in here, my dear?" Colonel Mustard called as he opened the door to Miss Scarlet's bedroom.
He let out a little grunt of disappointment when he discovered she wasn't in the room after all.
"Dаmn."
With mechanical force, he carelessly tossed the Rope in his hand on her bed and stepped inside in hopes that she might pop in after all. Of course, a thought occured.
"Usually, it is not polite for a gentleman to enter a lady's room," He thought with a lewd smile,
"Perhaps I should sweep her with force when she comes back...say...what's this?" Just then, he saw a telegram for Miss Scarlet resting on top of her vanity.
"Perhap's a little snooping wouldn't hurt..."