Miss Vivienne Scarlett

Stepdaughter of Mrs. Peacock, Miss Scarlett believes that she should have been heir to Arlington Grange and not Mrs. Peacock. But the estate is not the only thing that her stepmother has that she wants for herself.
Worried that Mrs. Peacock may cut her off finacially, did Miss Scarlett resort to other means to get money?
Here are some of the questions that Inspector Grey has asked Miss Scarlett. Try to read as few as possible before making your guess (by clicking on the "Murder Cards" icon above).
Were you blackmailing Dr. Black?
When did you wear the red velvet dress you were talking about?
What were you and Col. Mustard plotting?
What happened in the Dining Room?
What did you do with the Candlestick?
What happened once Col. Mustard had left you and your stepmother in the Ballrooom?