Story highlights Federal witness protection program helps government witnesses get new identities

People in program need protection because they've testified against criminals

Most people in the program aren't law-abiding citizens, program's creator says

"These people truly are in danger," a U.S. Marshals Service official says

Ever imagined what it would be like to be someone else for a day? How about for the rest of your life?

That's the reality for the thousands who have entered the federal witness protection program since it started in 1971.

Officially called the Witness Security Program, it provides protection for government witnesses who are at risk due to testimony they've given about terrorists or criminals.

"No one knows what we do to protect witnesses, and it's good for us," said David Harlow, associate director for operations with the U.S. Marshals Service, which oversees the vast program.

"It's about taking people and changing their way of life," Harlow added. "These people truly are in danger."

Photos: Photos: American gangsters Photos: Photos: American gangsters American gangsters – James "Whitey" Bulger rose to the top of the notorious Winter Hill gang, prosecutors say, before he went into hiding for more than 16 years after a crooked FBI agent told him in December 1994 he was about to be indicted on federal racketeering charges. He was captured in Santa Monica, California, in 2011, living under a false name with his girlfriend in an apartment in the oceanside city. On August 12, the gangster was found guilty on 31 of 32 counts -- including involvement in 11 murders. Here are some other gangsters from America's past. Hide Caption 1 of 10 Photos: Photos: American gangsters American gangsters – Al Capone, or "Scarface" as he was popularly known, remains one of America's most notorious gangsters. Known for wearing custom suits, fedoras and spats, Capone was infamous in 1920s Chicago for his bootlegging and racketeering activities. Capone died in 1947. Hide Caption 2 of 10 Photos: Photos: American gangsters American gangsters – New York Mafia chief John Gotti was known as "Dapper Don" for his expensive suits and "Teflon Don" due to government charges failing to stick in three trials. He was later convicted of murder and racketeering. He died of cancer at age 61 in 2002 while serving a life sentence. Hide Caption 3 of 10 Photos: Photos: American gangsters American gangsters – Henry Hill, a mobster-turned-informant for the FBI died in 2012 at age 69. His story was the basis for Martin Scorsese's acclaimed 1990 film, "Goodfellas." Ray Liotta played Hill in the film. Hide Caption 4 of 10 Photos: Photos: American gangsters American gangsters – George "Bugs" Moran was Al Capone's main rival in the Chicago mafia, culminating in the St. Valentine's Day Massacre in 1929 in which several members of Moran's gang were killed. Moran died in 1957. Hide Caption 5 of 10 Photos: Photos: American gangsters American gangsters – Clyde Barrow and Bonnie Parker robbed banks across America before meeting their end when police and federal agents ambushed them on a dirt road in Louisiana in 1934. Hide Caption 6 of 10 Photos: Photos: American gangsters American gangsters – John Dillinger, gangster and bank robber, was the first criminal to be called Public Enemy No. 1 by the FBI. Bureau agents gunned him down outside a movie theater in 1934. Hide Caption 7 of 10 Photos: Photos: American gangsters American gangsters – George "Baby Face" Nelson, a car thief by age 14, associated with the likes of Al Capone and John Dillinger. Nelson died following a shootout with the FBI in 1934. Hide Caption 8 of 10 Photos: Photos: American gangsters American gangsters – Mobster Louis Lepke Buchalter was one of the forces behind a hit squad known as Murder Inc. He died in the electric chair at New York's Sing Sing prison in 1944. Hide Caption 9 of 10 Photos: Photos: American gangsters American gangsters – Vincent "Mad Dog" Coll was infamous for the attempted kidnapping of a rival gang member in 1931. Coll shot into a crowd, killing a child and injuring several other youths. Coll escaped conviction due to a lack of credible witnesses. He was later shot to death in 1932 while talking in a phone booth, most likely by a rival gangster. Hide Caption 10 of 10

The program has made some limited information available to the public on its website: It provides 24-hour protection to all witnesses while they are in a high-threat environment; witnesses receive financial assistance for housing and subsistence for basic living expenses and medical care; the program also provides for job training and employment assistance.

In an interview with CNN, Gerald Shur, who created the program, offered insight into the inner workings of this secretive government service.

Shur was an attorney in what was then the Justice Department's Organized Crime and Racketeering Section in the 1960s when he developed the idea to protect witnesses.

"It occurred to me that we have to have a way that if a guy is in danger because of his testimony, we have to get him out of there, and in a second," said Shur, 79, who is now retired.

But the transition to a new life doesn't always come easily, he said.

"It takes time for them to adjust, " Shur said. "(A witness) not only has to deal with leaving his entire family, but he has caused his wife to leave her family; he's caused his children to leave their grandparents. They can't communicate. They can't see each other. But the driving force is 'If I go back, I'll be murdered.' "

Most witnesses who enter the program are not law-abiding citizens, according to Shur.

"Ninety-five percent of them are what we call criminals," he said. "Not everybody is a killer or a member of the Hell's Angels or the mob, but there are people who are doing business with criminals.

"They might say they were legitimate businessmen, but they would bribe people," Shur said, recalling the case of an engineer who bought off a mayor.

"He said it wasn't bad because that's how you do business in the city. In his mind, he wasn't doing anything criminal," Shur said.

While most witnesses are familiar with the criminal justice system, their loved ones are not and often must accept being completely cut off from everyone they know. "You're talking about wives, children, grandchildren -- they are the really innocent people," Shur said, "They are in it for life, as far as I was concerned."

The program is also completely voluntary. While witnesses and their family members are free to return to their former identities, they do so at their own peril, Shur said.

"I've had witnesses ask me if it's safe to go home. I never said yes. I always felt there was a risk still there," Shur said, "and that if a defendant against whom they testified is dead, there may be a family member out to get revenge or somebody within his organization who wants to be a hero of some sort and kill him."

Shur recalled two instances when witnesses refused protection. "(One witness) went back to his home and turned the doorknob and it blew up. And there was another witness -- we tried to talk her into it. She refused and she was murdered."

Henry Hill , the gangster who was the inspiration for the 1990 film "Goodfellas," opted out of the witness protection program, as did mob turncoat Sammy "the Bull" Gravano.

But those witnesses' decisions to leave the program make them the exception to the rule, Shur said.li

After a witness agrees to testify for the prosecution, he or she may be eligible to start receiving protection. Shur described an effective way of choosing where to relocate a witness.

"I would say to them, 'Tell me what's your favorite place in the U.S.?' " Shur said, "and they'd say, 'I always wanted to go to Hawaii,' or that they had family in Texas or Florida. And in my mind that's three places that they are not going. Because when you tell me you want to go to Hawaii, I know you have told all your friends that."

Deputy marshals take the witness and the witness' family and move them to another area, Shur said. Sometimes, they start in a hotel. Sometimes, they are near other witnesses -- although they'd never know it, he added.

"In the beginning when the witnesses were moved off to another city, we'd run into the problems you would expect -- what to do about a driver's license, Social Security cards, how do you get him a job, money, what happens if you need Medicare care, what about the house he owns, the furniture, and so on."

Witnesses get help finding a job, but they aren't always compensated.

"The program has nothing to do with reward money, nothing. They get money for a period of time, and then it stops," Shur said. "We used a formula. If you are a family of four in New York, you would get more money than a family of four from Corpus Christi. It's based on cost of living, and it wasn't based on the value of the testimony."

Shur said his work protecting witnesses put his family's life in danger. "There was a threat against my wife. I was told that there was an individual who had my name and my wife's name in his address book and that he had a contract from the Medellin Cartel to kidnap my wife and learn where a particular witness was living. And I immediately asked for protection for my wife."

Today's witness protection program faces the added burdens of the digital age. Facebook, Google, texting and the instant access to information via the Internet and smartphones provide new challenges to keep the identities of witnesses a secret.

"The modern world of technology, because there is more information out there, it's that much more important for our people to be vigilant and for us to be vigilant," said Harlow of the U.S. Marshals Service.

Vigilance plays a role, but Shur suggested another factor may also play an important role.

"Luck, you have to throw in some luck," he said. "You can't go this many years with this many witnesses without some luck in this thing."