Gerald Shur has spent a lifetime trying to understand the criminal mind.

The Bucks County resident has never been short on research subjects. Shur was the mastermind behind the creation of the federal witness-protection program, and throughout his 34 years with the Department of Justice, he thrust himself into the lives of the most vicious kingpins of organized crime in America.

Now retired, Shur, 74, can finally talk about his past, the program he founded, and the veil of secrecy under which he lived most of his adult life. (Despite the retirement, though, Shur maintains a low profile and asked that the town in which he lives not be disclosed.)

Since the witness-protection program began in 1970, more than 7,000 witnesses and 14,000 family members have been relocated with new identities. Shur declined to reveal any names except the first protected witness, the infamous Mafioso Jack Valachi, who gave up dozens of his mob friends. Years later, witnesses in the program helped bring down mob boss John Gotti.

"We do everything we can to help witnesses, including finding them jobs in their new locations, but we have strict rules," Shur said. "When you assume a new identity, you may never return to your past life. You basically forfeit your chance to attend your mother's funeral.

"There have been cases of witnesses sneaking back to see friends or relatives. A few have been killed, but we have never lost a witness who played by the rules."

The hazards extended to Shur's own life. An informant once told the Drug Enforcement Administration of a kidnapping plot against Shur and his wife, Miriam. An armed marshal passing for a student teacher was immediately dispatched to guard Miriam Shur while she taught second grade.

Another time, the Shurs' daughter, then a teenager, answered the phone and was asked: "Have you ever thought about death?"

Shur's passion for combatting organized crime was ignited by his father, a dressmaker in New York's garment district, where the Mafia, or Cosa Nostra, was firmly entrenched.

"My father was a member of the United Popular Dress Manufacturers Association, and he would complain about organized crime in the industry," Shur said. "He couldn't engage in the normal collective-bargaining process because the racketeers would interfere. His anger was the fuel that fed my fire."

In 1961, Shur had a law degree, a wife and two children, and a practice in Corpus Christi, Texas. That April, he read that Attorney General Robert F. Kennedy was planning to open an office dedicated exclusively to fighting organized crime. Shur later called the office of the new chief of the Organized Crime Section and was granted an interview. He flew to Washington the next day.

"I was hired without even having a resume," Shur recalled. "On my first day at work, the deputy chief said: 'Here's a list of investigations in New York City. Be ready to report to the attorney general tomorrow.' On Day 2, I met Bobby Kennedy."

As the new area coordinator for New York, and particularly Brooklyn, Shur met with Kennedy monthly to report on organized crime in his region. One of those meetings took place on the morning of the day that President John F. Kennedy, Robert's brother, was assassinated.

Shur remembers the catalyst for the inception of the Witness Security Program.

"An armed robber was holding up bookmakers so frequently that bookies who saw him approach would just hand over their money," he said. "The thief was eventually caught. While he was awaiting trial, a federal agent summoned me to the jail.

"The agent suspected that the prisoner had a tremendous amount of information, but refused to talk because he feared for his life. I grilled the guy, and for a long time he just blew air, but eventually he spilled valuable information that led to the capture of two men who had a contract to commit murder.

"I decided then that the key to nabbing the big guns would be to provide instant protection for potential witnesses. It was imperative to devise a system where you could pick up the phone and arrange for protection immediately."

James A. Cohen, professor of criminal law at Fordham University, has experienced Shur's program through his work as a criminal lawyer.

"The federal witness-

protection program has been an invaluable asset to federal law enforcement because it offers a significant measure of protection for those who report on other people's crimes," Cohen said, "or even on their own crimes."

The program's rules were developed by Shur, then the attorney in charge of intelligence and special services of the Organized Crime and Racketeering Section. Later, he became senior associate director of the Office of Enforcement Operations for the Department of Justice, and he held that position until his 1995 retirement.

Awards, commendations, and pictures of Shur with numerous attorneys general decorate his home. The most prestigious honor is the John Marshall Award, the highest award an attorney in the Department of Justice can receive.

Upon retirement from the Justice Department, Shur worked as a consultant in Annapolis, Md. He moved to Bucks County 19 months ago to be closer to his family and continues to consult for law enforcement agencies.

Asked what he has learned about the criminal mind, Shur said: "Not much. Some of these guys were brilliant. They could have run huge corporations, but something led them to a life of crime. Maybe it was the risk or the excitement or the glamour.

"I just don't know. I wish I did."