Pete Dinsmore was the father of Emily Dinsmore. After 6 years of experimenting, he successfully cloned her, but her clone was dangerous and it eventually killed him.
Mr. Dinsmore's daughter Emily drowned when she was just 10 years old while trying to save her friend, Lana Lang. After her death, he moved away from Smallville to Granville. The accident took a toll on his relationship with his wife and they got divorced. Eventually Pete began experimenting with cloning 6 years after Emily's death. He was able to use meteor rocks to accelerate the growth of cloned rabbits. When he applied this technology to his daughter, he had mixed results. He was able to clone Emily successfully, but the accelerated growth causes severe genetic defects; specifically, she had no moral center and no conscience. Emily also had the powers of super speed and a kinetic ability, making her especially dangerous. At one point, when she became frustrated with her father, she ran him through with a lawn ornament. He recovered, but he was not permitted to continue working on the project until they ran into trouble.
Emily learned that her super speed afforded her the additional ability to pass through solid objects. She walked right out of her prison, and Lionel asked Mr. Dinsmore to help him find her. Unfortunately, as soon as he found her, she killed him.
Pete Dinsmore's research about cloning his daughter Emily was mentioned when Tess was trying to find a cure for Alexander because he was aging rapidly. Dr. Christina Lamell said that she was able to use his research to develop a cure, but in the end Tess destroyed the serum because she knew Alexander was too dangerous to be allowed out in public.