By Rochelle Steinhaus
Court TV

It has the mob, ex-cons, international terrorists, millions of dollars at stake and priceless masterpieces. But the one thing the story of the biggest art heist in history doesn't have is an ending.

At least not yet.

It has been 12 years since a pair of thieves pretending to be police officers stole works by the likes of Rembrandt, Degas and Manet worth roughly $300 million from Boston's Isabella Stewart Gardner Museum. Even with the prospect of a $5 million reward, none of the 13 pieces has been found.

The probe has taken several interesting twists and turns, leading the FBI to focus on the Irish Republican Army, a Boston mob boss now on the lam and a notorious art thief who has been recently paroled. So far the art and the thieves remain at large.

Not a single person has been prosecuted in connection with the case — and now even if the thieves are caught they could be immune from prosecution because of a statute of limitations.

The investigation continues, however, to identify those who commissioned the robbery or possess the art — and of course, to recover the stolen works.

"It still is an active investigation," said Special Agent Charles Prouty, who heads up the Boston field office of the FBI. "It is an active investigation all over the world."

The crime

Two men dressed as police officers knocked on this door, the security entrance of the museum

Hours after St. Patrick's Day festivities wrapped up in Boston on March 18, 1990, two men dressed as police officers knocked on the security entrance side door of the Isabella Stewart Gardner Museum at 1:24 a.m.

The pair of "cops" told the two security guards on duty they had received a report of a disturbance in the museum's garden, located in the center courtyard of the 15th-century Venetian-style palace that was once home to the museum's benefactor, turn-of-the-century socialite Isabella Stewart Gardner.

Though it was museum policy not to allow anyone — not even police — inside the museum at night, the security guards opened the door.

The courtyard of the Isabella Stewart Gardner Museum

"The policy has always been that you don't open that door in the middle of the night for God. Why on this one night they opened the door no one can explain," Lyle Grindle, the museum's current head of security, told Access Control & Security Systems, a security industry trade publication. Grindle was not in charge of security at the time of the 1990 heist.

Just minutes after letting them in, the guards quickly learned that the late night visitors weren't real cops.

Though they apparently did not brandish any weapons, the intruders managed to overpower the two guards. They handcuffed the guards, bound them with duct tape and left them in the basement.

In the fewer than 90 minutes that followed, the bandits went through the museum's Dutch Room on the second floor and stole three Rembrandts, including the Dutch artist's only seascape, "Storm on the Sea of Galilee." (See map, with stolen artworks.)

It was one of several works the thieves savagely cut to release it from its frame, leaving ragged edges of the canvas behind in otherwise empty frames, which continue to hang in the museum to this day.

Also taken from that room was "The Concert" by Vermeer, as well as a Chinese bronze beaker located near the Rembrandt.

Vermeer's The Concert

The thieves also apparently tried to steal a fourth Rembrandt but were unsuccessful.

"They tried to pry the wooden frame," explained Prouty during a recent interview in his Boston office.

Nearby, they also made off with "Landscape with an Obelisk," an oil painting by Govaert Flinck that was until recently attributed to Rembrandt, Flinck's mentor.

On the other side of the floor, the thieves went into the Short Gallery and ripped five Degas sketches from the wall. Feet away a bronze eagle that adorned the top of a Napoleonic flag was also pillaged.

A Manet portrait, located in the museum's Blue Room on the first floor, capped off the list of works the thieves stole.

Chez Tortoni, by Manet

Oddly enough, the third floor — where the Titian Room showcases "The Rape of Europa," since voted the city's most significant piece of art — went untouched.

It is not known in what order the rooms were ransacked, since the thieves ripped out the surveillance tape before fleeing the museum with it.

To this day, the small museum isn't able to collect insurance, since it carried no insurance policy at the time of the heist.