The leak of question paper

When Carl Black came back, he saw Rosaline Moore standing in front of his cabin. Surprised, he frowned and asked, "Professor Moore, is everything alright?"

She smiled and said, "Oh yes, everything is fine." Taking out the key from her purse, she passed it to him and explained "I think you dropped it in the canteen and I thought it is mine, so I picked it up. But mine was in my office." She was smiling at him.

Carl Black took the key and said "Thank you."

"You are most welcome. Then I will leave now." She walked away with long strides from there immediately.

Carl Black looked at her leaving figure coldly. During his 5 years of work in this college he hardly talked to her, but today she came to him on her own to wish him. Her behavior was suspicious, but he didn't know what she was trying to do. Shaking his head, he went inside his cabin.