While accused robbers in the Philadelphia court system enjoy great odds of beating their cases, the rules are different at Sixth and Market Streets.

The lawyers know it. The police know it. And defendants soon figure it out once they hear two very potent words: federal court.

Since 2001, federal prosecutors have targeted about 2,000 defendants in the city court system and initiated firearms and robbery charges in federal court, where a 95 percent conviction rate and tough sentencing laws routinely lead to prison terms of 20 years or longer.

"We're trying to put a stop to as many of these crimes as we can," said Assistant U.S. Attorney Robert K. Reed, who oversees the unit that handles firearms and robbery cases. "We want to get this message out: If you come into federal court, you will face up to life in prison."

About 200 Philadelphia cases a year end up in federal court under the Justice Department initiative, known as Project Safe Neighborhoods. Many of these involve defendants who have repeatedly won their cases in city courts, where an Inquirer analysis found that even in the most basic gun-possession cases, only 56 percent of defendants charged in 2007 were found guilty of any crime.

A task force made up of city and federal prosecutors as well as representatives from the police, the FBI, and the Bureau of Alcohol, Tobacco, Firearms, and Explosives meets regularly to identify the most dangerous robbers or defendants whom investigators believe could provide important information about unsolved crimes.

If those defendants violated federal law in the course of their criminal activity, Reed said, their cases are taken before a federal grand jury for indictment. Two federal statutes in particular have proven useful.

One statute is used to go after robbers who hit gas stations, convenience stores, and other businesses. The other is a federal law that mandates a minimum of seven years behind bars for first-time offenders who brandish a gun in a violent crime, and 25 years for repeat offenders - on top of whatever they get for the underlying crime.

The average sentence for all firearms cases over the last eight years has been 9.5 years in prison, according to statistics compiled by the U.S. Attorney's Office, with robbery cases resulting in average sentences of 17.7 years.

Stephanos Bibas, a law professor at the University of Pennsylvania, said the federal firearms law is so tough that it encourages defendants to plead guilty in an effort to win at least some reduction in sentence.

"It gives prosecutors an enormous club," said Bibas, who said that a federal defendant who commits three robberies could otherwise easily end up with a sentence of 50 years in prison.

Pennsylvania's mandatory minimum laws for serious gun crimes are regarded as weaker because judges can sidestep the five-year mandatory minimum in violent crimes in which a gun is brandished by finding a lower degree of felony.

The strict federal laws also put pressure on defendants to cooperate - a cultural shift from the anti-snitch attitude that has hamstrung cases in the Philadelphia court system for years. But cooperating with law enforcement is about the only way to get a substantial break in sentencing at the federal level.

"We generally give everyone the opportunity to talk to us - to cooperate in other matters - to substantially reduce the sentence. It's a way for us to build other cases," said Reed, who said the collaboration with city prosecutors and police had helped solve about 200 homicides since 2001.

But it's not just the long sentences that make federal court a more hostile arena for defendants.

Assistant U.S. attorneys have more time to build a case than do harried assistant district attorneys, who often get dozens of cases to prepare the day before they are due in court.

Federal prosecutors also have the ability to compel people to testify before a grand jury.

"That is a huge difference," Reed said. "We don't have the same volume, but in the cases we do handle . . . we're able to develop our case far more extensively."

Even reluctant witnesses can be ordered to appear before a grand jury - under threat of jail - to testify about what happened.

Robert E. Welsh Jr., a former federal prosecutor who is now a white-collar defense lawyer, said that because there are no preliminary hearings in U.S. District Court, federal prosecutors don't have to worry about producing witnesses at an early point in a case.

"That eliminates an entire stage for witnesses to bail out. That is hugely important," Welsh said. "Every one of these court appearances is an opportunity for witness intimidation or witnesses' losing interest."

Federal prosecutors also rely on a tough pretrial detention law that allows defendants to be jailed pending trial if it can be shown that they pose a danger to the community or might flee. That means they are not entitled - at all - to bail.

Not surprisingly, the vast majority of federal firearms and robbery cases end in guilty pleas. Only about one in seven defendants opts for a trial. Those who do face generally more conservative jurors who are drawn not only from Philadelphia, but also from more rural counties such as Lancaster, Lehigh, and Northampton.

But Welsh and other legal experts caution against using the federal courts to go after all robbers and gun offenders. That, they said, would overwhelm the federal system and sap the prosecutorial resources that are needed for the more traditional federal cases involving complex fraud, racketeering, and corruption.

Considering that more than 3,000 cases of gun robberies, gun assaults, and gun possession are initiated each year in the Philadelphia courts, federal authorities say, they have to be selective.

Vernon Bryant, for example, had four felony and drug cases in Philadelphia Common Pleas Court. He ended up with some jail time, but always less than two years. In one case, for example, he pleaded guilty to robbery and was sentenced to nine to 18 months behind bars.

But he attracted the interest of federal prosecutors after he was arrested in November 2003 near 60th Street and Haverford Avenue in West Philadelphia after police went to the area because of information that a gunfight was about to begin.

As detectives approached the corner, Bryant started to run, reached into his waistband, and tossed out a black Colt .45-caliber semiautomatic handgun with five live rounds in the magazine and one in the chamber, according to court documents.

Bryant was charged federally with possession of a firearm by a convicted felon. He pleaded guilty - and is now serving a 15-year sentence.

Jawan Oaks also ended up with a federal case.

Oaks had been charged in Philadelphia courts with drug possession in 2004 and with the March 2005 robbery of a deliveryman for a restaurant.

While the drug case was pending, the robbery case was dismissed - after at least six postponements - for lack of prosecution.

Then, in 2006, Oaks carried out four carjackings and three gunpoint robberies, including one in which he shot and wounded the victim in the buttocks after declaring, "I'm a killer. This is what I do," according to court records.

Assistant U.S. Attorney Arlene D. Fisk, a former homicide prosecutor in the Philadelphia District Attorney's Office, said Oaks was a good example of the kind of defendant slated for federal prosecution.

"He had multiple open violent offenses," Fisk said.

According to police charges filed before his case was transferred to federal court, Oaks and a codefendant approached a man coming out of a Southwest Philadelphia store.

Oaks pointed a gun at him and took off in the man's blue Chevy van, according to charges.

Oaks was indicted by a federal grand jury on May 29, 2007, on charges of armed carjacking and carrying a firearm during a crime of violence. Conviction of the latter charge carried a mandatory minimum sentence of seven years on top of whatever he got for the carjacking.

The case was strong because Oaks had confessed to the carjacking when he was arrested by Philadelphia police. He pleaded guilty in U.S. District Court.

Fisk said the federal firearm statute is generally a "very effective" weapon in gunpoint-robbery cases transferred from Philadelphia's overburdened court system.

"It's more difficult in the state system, just because of the number of cases," Fisk said.

In June 2008, Oaks got his federal sentence: 91/2 years.

City prosecutors, meanwhile, still had a shot at him.

Though Oaks' 2005 heroin-possession case was withdrawn in September 2007, city prosecutors refiled charges in the case of the robbery of the deliveryman for the restaurant, and two other cases were pending from his series of carjackings.

On May 18, 2009, Oaks pleaded guilty in all three cases and is now in prison for five to 15 years.

Contact staff writer Emilie Lounsberry at 215-854-4828 or elounsberry@phillynews.com.

Inquirer staff writer Nancy Phillips contributed to this article.