who was Lowell Lee andrews? why was his story in the book?

"Lowell Lee Andrews was an 18 year old honors student at Kansas State University when, over the Thanksgiving Day weekend of 1958, he murdered his parents and older sister. Andrews is mentioned in Truman Capote's book "In Cold Blood." Having never expressed remorse for his crimes, he was hanged on November 30, 1962. The following day, he was buried next to his three victims."

Capote did massive amounts of research before writing this novel, and he included everything that went along with his story. Andrews was included in the novel because he fit into the plot and served the author's purpose of making the novel as factual as possible.