He started researching their lives, reading biographies and interviews. Some of the richest material came from Jennings Faulk Carter, Mr. Capote’s cousin and a frequent co-conspirator during Tru and Nelle’s escapades. Mr. Carter gave a detailed oral history to Marianne Moates Weber for her book, “Truman Capote’s Southern Years.” “These stories were amazing — they were colorful and outrageous and funny and tragic,” Mr. Neri said in a telephone interview from Tampa, Fla., where he lives. “Tru & Nelle” hews closely to history. It opens with their first encounter one summer in Monroeville, when Nelle was 6 and Truman 7, and ends with a dramatic scene with hooded Ku Klux Klan members arriving at a Halloween party that Truman was hosting. According to an account given by Mr. Capote’s cousin, Klan members came because they heard African-American guests had been invited to the costume party, and left after Nelle’s father, A. C. Lee, confronted them.
The novel ends on a bittersweet note, when Truman leaves for New York not long after the Halloween party, when he is about 8 years old. The real story was much messier, though.
Mr. Capote continued to visit Monroeville in summer. He published his first novel in his early 20s. Ms. Lee, encouraged by his success, moved to New York to write when she was 23, despite her family’s misgivings.
But their friendship was strained by bitterness and rivalry. Mr. Capote envied the success of “Mockingbird,” which won the Pulitzer Prize. Rumors spread alleging that he had written “Mockingbird” for Ms. Lee. She was stung when Mr. Capote relegated her to the acknowledgments of “In Cold Blood,” after she helped to research it and contributed 150 pages of typed notes. Toward the end of his life, Mr. Capote drank and used drugs heavily, alienating many of his friends, including Ms. Lee. He died of liver disease at the age of 59. “Drugs and alcohol did not cause his insanity, they were the result of it,” Ms. Lee wrote to an acquaintance.
Literary influence is hard to measure, and it’s impossible to say how Harper Lee and Truman Capote might have developed creatively in isolation, had they not spurred each other on as young writers.
Mr. Neri offers a theory toward the end of his novel, when Tru proposes a pact: “ ‘I’ll make you a deal: I’ll write, but only if you promise to write as well. Then we can mail each other our stories,’ he said, hopeful.”
