Back home in Elizabeth, N.J. after 11 melancholy years, Nate Walker was savoring his first taste of freedom. Walker took a bite of Danish pastry and munched it with the joie de vivre of a man newly liberated from the dreary routine of prison food. "I'm happy just to see trees, sky and grass," he said. "I'm happy just to drink coffee and sit and talk. I'm happy to be back home."

Nate Walker had been a forgotten soul, serving "life plus 50 years" in a maximum-security penitentiary for a rape and kidnapping he didn't commit. Vainly and repeatedly he had protested his innocence. And then, just when he had begun to surrender hope, Walker had encountered an unusual character named James McCloskey, a businessman turned seminary graduate whose sense of mission was equalled by his remarkable skills as an amateur detective.

McCloskey labored on Walker's case for more than a year, building a dossier of exculpatory evidence so indisputable that this month the Union County, N.J. prosecutor's office recommended Walker's release. "Jim McCloskey," says Walker, invoking his liberator's name with gratitude and reverence. "There's not another man on the face of the earth like him."

There were times as he sat alone in a cramped prison cell that Walker nearly felt compelled to accept his fate. His appeals in the state courts were exhausted. His lawyers had long since moved on to new cases, new trials. His mother, Irene—always believing in his innocence—organized rummage sales at the Grace Episcopal Church in Elizabeth to raise money for a last-hope legal effort. But it looked fairly certain that Walker would remain in jail until his first opportunity for parole—in the year 2001.

Then, in September 1984, a fellow inmate introduced Walker to Jim McCloskey—a balding, robust-looking man whose worldly ebullience went hand in hand with a deep sense of spiritual mission. "Before Jim came into our lives, we were at a crossroads," says Walker's mother. "We couldn't afford a lawyer and we didn't know where else to go. I really felt that God sent Jim to us—and I know that Nate felt the same way."

In fact the 44-year-old McCloskey was anything but a traditional man of God. A Bucknell graduate and a Naval officer during the Vietnam War, McCloskey had spent the '70s hustling toward a partnership in a prosperous Philadelphia consulting firm, eyeing a life of suburban affluence. Still, "there was this gnawing sense of emptiness in the business world," he says. "It began to lose its redeeming sense of purpose for me."

To fill that void, McCloskey began attending church services. He kept his internal struggles private until in late 1979 he announced to his incredulous parents and colleagues that he was quitting the firm to enroll in the Princeton Theological Seminary, forfeiting a salary of $60,000 a year to train as a Protestant minister.

"As soon as I made the decision, I felt a great sense of joy," he says. "Even today when I drive by an office building or corporate park, I say, 'Thank God I'm not there.' Many of those people are miserable. I might not have money—but man, I'm glad it happened."

In 1980, as part of his course of study, McCloskey elected to spend one year doing field work at Trenton State Prison's "lock-down unit"—120 cells reserved for the prison's most troublesome inmates. He overcame his natural fears, learned to ignore the taunts of radical Black Muslims and formed close relationships with many prisoners. Through one of them, four years later, he met Nate Walker.

In due course Walker told McCloskey his story. He recalled the cold February night in 1975 when six policemen came to his apartment, took him downtown and put him in a lineup. He remembered his horror when told that he had been identified by a 21-year-old Elizabeth, N.J. woman as the assailant who had abducted and raped her at knifepoint four months earlier. Sentenced in June 1976, Walker appealed. In 1978 the New Jersey Appellate Court overturned the conviction on a technicality, ordering him released from Rahway State Prison on $2,500 bail to await the prosecutor's appeal. When the State Supreme Court reinstated the sentence in 1979, Walker fled. A fugitive from justice, living under an assumed name with his wife, Sharon, in Los Angeles, he managed an apartment building and prayed the FBI would forget he ever existed.

It didn't. In 1982 federal agents tracked Walker down, returning him in handcuffs to Trenton State Prison.

From the start McCloskey was appalled by the seeming arbitrariness of Nate Walker's arrest. Apparently several prior arrests for auto thefts made him an easy police target. McCloskey read through 500 pages of trial transcripts and police records, talked to Walker's relatives and friends and gradually became convinced that the prisoner was an innocent man.

Walker appeared to have a solid alibi: A colleague was driving him home from his night shift job at a copper products factory at the time the rape occurred. Walker bore no physical resemblance to the victim's description of her assailant: She claimed the rapist was in his early 20s and wore no glasses, while Walker was 33 and nearly blind without his thick lenses. Moreover, McCloskey claims, the victim herself had a history of drug problems and tangles with the police—credibility-damaging factors about which the original jury had never learned.

Anxious to confront Nate Walker's accuser, McCloskey scoured the city of Elizabeth, interviewing neighborhood shopkeepers who led him to the victim's rabbi, her former acquaintances and family. Ultimately he tracked her to a Florida town. "When I found her," he recalls, "she told me, 'Mr. McCloskey—I have absolutely nothing to say to you.' I was terribly disappointed."

Then came the breakthrough: Under constant pressure from McCloskey and attorney Paul Casteleiro, the county prosecutor located a 12-year-old semen sample that had been taken from Walker's accuser the night of her rape but never examined. It had been gathering dust in a corked bottle in the property room of the Elizabeth Police Department. The FBI analyzed the specimen and detected evidence of both A and B blood types. Next, Walker's blood was tested and found to be type A. Then, thanks to McCloskey's sleuthing, the prosecutor was able to reach the rape victim in Florida and persuade her to give a blood sample. The victim also tested as type A. The conclusion was inescapable: The type B antigens came from another man—the actual attacker—and Walker was innocent. Five days later he was released.

"I told the other inmates I was going home, but they didn't believe me," says Nate. "They said, 'Nobody ever gets out of Trenton State Prison. When you're here, you're in for life.' "

The phone rings insistently in the Victorian parlor of the Princeton, N.J. house where Jim McCloskey is a lodger. A New York talk show host wants to book him; reporters and photographers lay rival claims on his time. Hollywood producers began calling 10 days ago, eager to snap up the movie rights to his suddenly famous life.

Upstairs, in his bedroom office, the ruddy-faced minister is astonished at the reaction to Walker's liberation: "I feel bowled over." The case is a major success for McCloskey's "Centurion Ministries," the tax-free one-man organization he established three years ago to "free and vindicate the innocent from life sentences." Before Walker, his investigations led to the exoneration of two men who had been convicted of murder. To his dismay, one has returned to a life of drugs and jail. The other has long since been deported to the Dominican Republic on a legal technicality.

Still such setbacks have not lessened McCloskey's commitment. "People are saying, 'You're wasting your gifts on one individual here, another one there.' But I vehemently disagree," he says. "Prosecutors and judges will claim that the Walker case is an aberration—that an innocent man goes to jail one out of a hundred times. But I think it's more like one in 10."

Law enforcement officials may object to his statistics. But Nathaniel Walker, for one, takes stock in McCloskey's words. Today he is broke and jobless, searching the want ads and contemplating legal action for unjust incarceration. For the moment, he says, the freedom that McCloskey has brought him is enough. "Jim gave me hope and encouragement in my darkest moments," says Walker. "Without him, I'd still be in hell."