Clue by Clue: Murder of a Millionaire Solution
Mr. Mulligan was killed by Mr. Hartley, who suspected that Mr. Mulligan was going to ruin the company. Mr. Hartley knew about the secret door between the bedroom and the office, so when Mrs. Mulligan and the Johnsons were distracted by the shooting stars, at about 8pm, he slipped through the bedroom door from the balcony and opened the secret door to the office. He saw that Mr. Mulligan was writing documents to close TeleCom, Inc. and open a charity. Afraid he would lose his job, Mr. Hartley grabbed a sword off the wall and stabbed Mr. Mulligan through the heart and then stole the paper. He locked the door, left through the secret door and quietly came back on the balcony, just in time to hear the lawyer return and start shouting.