Happy Birthday, Mr. Monk - S8-E9
Question: At his birthday party, Monk realises that Pressman is the murderer and when he looks at his ice cubes, he sees that they are square while everybody else's is round. He then realises that the poison was in the ice cubes and now his ice cubes were filled with poison. Why would Pressman try to kill Monk? He never did anything that gave Pressman the indication that he was on to him. All Monk did was want his self-cleaning vacuum fixed.
Answer: When Natalie and Monk took the vacuum cleaner to Pressman, Pressman asks about the cases they're working on, and after Pressman mentions the janitor cases, Natalie says that Mr. Monk always says "it's a work in progress" when he's close to solving the case. Pressman was afraid Monk would figure out the connection of the two cases soon.
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