David Garrow’s books include “The FBI and Martin Luther King, Jr.,” the Pulitzer Prize-winning King biography “Bearing the Cross” and “Rising Star: The Making of Barack Obama.”

Jack O’Brien graduated from Washington and Lee in 1984 with an Oxford fellowship and an acceptance from Yale Law School in hand. A few weeks later, he changed his name back to the one he had at his birth: Jack Goldsmith.

Why? In June 1975, when Jack was 12, his mother, Brenda, married her third husband, Charles “Chuckie” O’Brien, a longtime Teamsters union factotum. Six weeks later, the former Teamsters president to whom O’Brien had dedicated most of his life, James R. “Jimmy” Hoffa, disappeared from a suburban Detroit parking lot, his body never to be found. Almost immediately, O’Brien was fingered as the likeliest suspect in Hoffa’s abduction and murder, in part because he had long served as Hoffa’s intermediary to the organized-crime families whose support Hoffa had welcomed. O’Brien’s mother, Sylvia Pagano, was a mob family daughter whose long relationship with Detroit underboss Anthony Giacalone helped grease the intimate ties between La Cosa Nostra and Hoffa’s powerful union.

For 12-year-old Jack, O’Brien’s arrival in his life was the best thing that had ever happened. Chuckie “glommed on to me with love and attention that I had never received from . . . anyone else,” and he became “an extraordinary father to me and my brothers.” Listening to Chuckie’s tales of years past, “I thought of Jimmy Hoffa as the grandfather I’d never met,” and “I proudly changed my name to ‘Jack O’Brien.’ ”

In college, however, as he recounts in his new book, “In Hoffa’s Shadow,” Jack began reading the manifold stories about Chuckie’s Mafia ties, and as he considered his future, “I began to worry that the association with Chuckie might jeopardize my legal career.” After he finished Yale Law School, a judicial clerkship led to an FBI security clearance interview in which Goldsmith expressed “total disdain and disgust” for his stepfather, telling two agents that “he hopes he never sees or talks to ‘Chuckie’ O’Brien again.”

Reflecting on his behavior then, Goldsmith writes that “I renounced Chuckie out of apprehension about his impact on my life and my career,” attributing his actions to “ambition augmented by feelings of moral superiority.” A Supreme Court clerkship, two law faculty posts and a George W. Bush administration appointment followed, but when Goldsmith’s new wife witnessed his chilly rudeness toward his mother’s partner, she reproved him. “He loves you so much, you should be kinder to him.”

In mid-2003, Bush administration heavyweights moved to promote Goldsmith to a top Justice Department job as assistant attorney general for the Office of Legal Counsel. Thanks to his documented disavowal of O’Brien, Goldsmith received a top-secret security clearance without delay but soon was deeply enmeshed in multiple legal controversies growing out of the administration’s aggressive war on terrorism. As emotional pressures grew, Goldsmith found himself pondering “the Justice Department perch that I had reached only because I had renounced Chuckie” in what he now viewed as “a self-serving effort to maintain my reputation and advance my career.”

Goldsmith left his Justice Department post in mid-2004 to accept a professorship at Harvard, and parenting his own young children “led me to feel terrible about what I had done to the man who had been a wonderful father to me.” That Christmas he apologized to Chuckie: “I was wrong and selfish to treat you as I did all these years. I hope you will forgive me.” Chuckie, of course, did.

Eight years later, as a further act of atonement, Goldsmith began work on this book. Common knowledge aside, “I never believed Chuckie was involved in killing the man he so obviously revered,” because years of listening to O’Brien had shown him how “Chuckie loved Jimmy Hoffa more than anyone.” Yet the second father figure in Chuckie’s life, “Uncle Tony” Giacalone, whom like Hoffa he had known since age 9, had said enough to O’Brien in the wake of Hoffa’s disappearance for Chuckie to know why the mob had killed him. No longer Teamsters president following a stint in federal prison, Hoffa spoke recklessly about the mob’s control of the union. “People expected me to keep him quiet. But I couldn’t,” Chuckie confessed to Goldsmith. Two days after Hoffa’s disappearance, Giacalone took O’Brien to dinner. “Life is very funny, Chuck. Very funny. Things happen, and you don’t have control over it,” Uncle Tony told him, while warning, “Don’t talk about s--- you don’t know about.”

Goldsmith explains that Giacalone “was telling Chuckie that he, Uncle Tony, could not have stopped it from happening,” and two months later Giacalone reinforced his message by summoning O’Brien to a backyard meeting with Genovese family capo Anthony “Tony Pro” Provenzano, another top mobster whom Chuckie had long known thanks to his mother. Hoffa “had lost his f---ing mind and he was going to take everybody down,” Provenzano told O’Brien.

Chuckie understood that “Provenzano had a lot to do with it,” as he admitted to Goldsmith, but O’Brien also knew enough about the mafia to appreciate that what Goldsmith calls “one of the most brilliantly executed murders in American history” had been authorized by the mafia’s high command. “New York had to approve it,” he explained to Jack.

Goldsmith concludes this emotionally powerful and utterly compelling book by explaining that Uncle Tony’s brother Vito Giacalone probably lured Hoffa to his death and that the actual killer was a low-level Mafiosi who died this year. But “In Hoffa’s Shadow” is highly impressive not only as a nonfiction murder mystery but also as a work of profoundly apologetic filial love.

In Hoffa's Shadow

A Stepfather, a Disappearance in Detroit, and My Search for the Truth

By Jack Goldsmith

Farrar, Straus and Giroux.
354 pp. $28