Rufus Sewell as Dr. Jacob Hood – a science adviser to the FBI, called in to investigate crimes that may have a scientific explanation. Though Hood is extremely brilliant, he sometimes gets lost in his own thoughts, and this, coupled with his low attention span and poor social skills, causes him to be viewed as odd. He also has few instincts of self-preservation or danger, causing him to often do things that put his life in jeopardy, such as standing in front of a fleeing suspect’s car to get the license plate, something that frequently annoys Rachel. Additionally, he does not know how to drive well, leading Rachel to insist she do all the driving. Hood appears to be an atheist and is knowledgeable on a number of scientific, mathematical and philosophical topics. He nursed his wife, who died of cancer, throughout her illness.