Clue by Clue: Death of a Writer Solution
Sofia, his wife, killed him. She was planning to leave him and probably wanted to keep his money or make sure he didn’t try to stop her. She poisoned his coffee in the morning. Nathan went into his office and then drank the poison and died. No one would have checked on him because he liked to be alone.
After Sofia left the house, she went back inside. She set the clock to 10:03. She waited until her daughter started the car and then shot the clock and her husband. The dust near the clock was because she didn’t put it in quite the right place. That made it look like he died from the gunshot at 10:03 and not the poison earlier. The card from the gun club was hers so it seems possible she would have the experience needed to set up the shot to hit her husband and the clock behind him.
Crystal has a pretty good alibi. She was in town where she was well-known and then at the lake far from the house. She also has no motive and she left the house at 8:15. Mr. Rivera got his coffee after that, so he must have been alive after she left.
Valery has a sort of motive. He was stealing from the family for years. But no one had discovered his secret, so it’s not clear why he would have killed Mr. Rivera today. It also seems unlikely he would have visited the pond after killing Mr. Rivera since the pond was in the center of town.
Sara has a motive as well. Mr. Rivera didn’t like her fiancé and it seems that he wrote her a letter breaking up with her. However, since she was shopping for a wedding dress with her mother, it seems likely that he changed his mind.
So Sofia is the best suspect because she has motive and opportunity and the ability to commit the crime. It; would also explain her strange behavior when she left the house with her daughter. Engines don’t need to warm up in the sun!