WILMINGTON, Del. >> Federal prosecutors said Friday that four men arrested in the theft of a $2 million ruby from a Delaware jewelry store are tied to a ring that committed several similar smash-and-grab heists in Pennsylvania and New Jersey.

A December indictment unsealed Thursday in Delaware details allegations about the theft ring. A superseding indictment was filed and final arrest made that same day in connection with the Pennsylvania and New Jersey robberies.

Delaware prosecutors said the suspects, none of whom was arrested in Delaware, are all Pennsylvania men with no ties to Delaware but a history of crime, including serving time for armed robbery.

“These are essentially professional armed robbers. … These are hard-core defendants who have been around the block,” U.S. Attorney Charles Oberly III said.

Despite the arrests, authorities indicated that they have little hope of recovering the 5-inch, 4-pound Liberty Bell Ruby, a replica of the Liberty Bell sculpted from the largest mined ruby in the world.

“I don’t think there is an expectation right now at this point, two years after the robbery, that we’re going to be able to locate it,” Assistant U.S. Attorney Jamie McCall said.

The ruby was among several pieces of jewelry valued at a total $4.4 million stolen in a brazen November 2011 robbery of Stuart Kingston Jewelers in Wilmington. The robbery was featured in a 2012 episode of the television show “America’s Most Wanted.”

McCall said the robbery was planned carefully, with the thieves studying the layout of the store and using rental vehicles with stolen license plates to make their getaway.

Darrell Williams, 43; David Story, 46; Rufus Lawson, 48; and Willie Hawkins Smith, 22, all of Philadelphia, are charged with conspiracy, robbery and use of a firearm in furtherance of a crime of violence in connection with the Stuart Kingston robbery. All four face maximum sentences of life in prison if convicted on the firearm charge. The robbery and conspiracy charges carry a maximum penalty of 20 years in prison apiece.

Williams, Story and Lawson also are among eight defendants named in the indictment filed in Philadelphia involving the Pennsylvania and New Jersey robberies.

Authorities declined to provide details on how the theft ring was uncovered, but Oberly indicated that the 2012 arrests of Lawson, Story and James Lee Howard, an unindicted co-conspirator in the Delaware theft, were key to the investigation. Lawson was arrested for a probation violation; Story and Howard were arrested on separate robbery charges.

“They led to evidence … that resulted in the arrests of other individuals,” Oberly said of the three arrests. “It started the ball rolling.”

Howard and a co-defendant, Santo Fando Wadlington, pleaded guilty in the attempted robbery of a jewelry store in Lancaster, Pa., in June 2012. They are scheduled to be sentenced in June. Both men, along with Smith, are named as unindicted co-conspirators in several Pennsylvania jewelry store thefts.

An attorney for Howard did not immediately return a telephone message Friday. It was unclear how many of the other defendants have attorneys.

Officials with a California foundation that owns the ruby did not immediately return telephone and email messages.

In addition to the Delaware robbery, prosecutors allege that the theft ring was responsible for at least eight other robberies in Pennsylvania and New Jersey from July 2011 through November 2012. Authorities say those robberies netted jewelry valued at about $3.5 million, including $1.7 million from a single store in King of Prussia, Pa., that was robbed three times in a period of 13 months.