Anthony Amore, head of security at the Isabella Stewart Gardner Museum since 2005, still fields tips on the heist.

The Providence Journal / John Freidah

There is someone out there in the world who knows who conducted the biggest art theft of all time. There is someone, somewhere, perhaps, enjoying the beauty of artwork valued at a half-billion dollars.

Eighteen years after two men posing as Boston police officers outwitted two security guards and stole 13 works of art from the Isabella Stewart Gardner Museum, in Boston, the mystery remains.

Who was behind the heist? Where is the artwork now? Will the pieces ever be returned to their places within the museum, where the late Mrs. Gardner had arranged them herself a lifetime ago?

The museum’s director of security, Anthony Amore, talked about the heist on Friday as part of the University of Rhode Island’s continuing series of forensic science seminars. Amore, who graduated from URI with a degree in English, went on to a career in national security and intelligence work, including as a special agent for the Federal Aviation Administration and most recently as assistant federal security director at Boston’s Logan International Airport.

Amore, who has worked for the Gardner since 2005, said he has reorganized and improved training for the security guards and upgraded the security and surveillance equipment. But the empty frames hung on the walls where the stolen paintings used to be are a reminder of the museum’s loss. “The people who took these things [committed] the ultimate selfish act,” he said.

Amore said he often fields tips about what may have happened to the art work, even some bizarre ideas –– that the paintings are hidden in secret passageways within the Gardner, that the late Mrs. Gardner is communicating with psychics to tell them where the art work has gone. He said he has reviewed every file, every piece of evidence, and organized all he knows into a database that references and cross-references names and information, in hopes of making a connection.

But the $5-million reward offered by the Gardner for the return of the art work, or information leading to the return, still stands. The frames are still empty. And on March 18, it will have been 19 years since two men walked out with some of the most valuable artwork in the world, and disappeared.

Art theft is the third-highest-grossing criminal trade, Amore said, behind drugs and firearms. When the value of artwork spiked in 1961, when the Metropolitan Museum of Art bought a Rembrandt for $2.3 million, criminals took notice. Organized crime became involved. Fifteen years later, 118 Picassos were stolen from museums in France, he said.

Bold actions and basic human error left the Gardner Museum vulnerable. Two young guards were working that night, in March 1990, as St. Patrick’s festivities wound down, when two men dressed as Boston police officers approached the employee entrance and said they were investigating a disturbance and needed to come in.

Despite the museum’s written security policy not to admit police officers into the building unless they had been summoned by the museum, the guard let the “officers” in anyway, which Amore called “one of the biggest mistakes ever made.”

They asked him to call the other guard down to meet them. They lured the first guard away from his control desk, where he could have set off the alarm button, by telling him they thought he had a warrant. The “officers” ordered him against the wall and handcuffed him. When the second guard arrived, they handcuffed him as well. And then, Amore said, the intruders told the guards: “Gentlemen, this is a robbery.”

Amore flashed pictures on a screen of the washbasin where one guard was handcuffed, and the basement pipes where the other was taken, 40 yards away. The guards had been bound with duct tape. The thieves stripped the motion-detector readouts and broke the printer, not realizing that the authorities would be able to track their moves recorded on the computer’s hard drive.

Other museum heists have been quick smash-and-grabs, thieves overpowering guards and hustling out with what they wanted. Even the famous theft in 1911 of the Mona Lisa from the Louvre happened quickly, when museum worker Vincenzo Peruggia lifted the painting off the wall and carried it out under his arm. (He wanted to return da Vinci’s painting to Italy, but gave up and gave it back two years later.)

With the only two guards under control, the thieves in the Gardner had all the time they wanted. They sliced Rembrandt’s Portrait of a Lady and Gentleman in Black out of its frame. Amore showed a rarely seen close-up photo of the stretcher and the edge of canvas where a thief had sliced to remove the image.

The thieves pulled down Vermeer’s The Concert and Manet’s Chez Tortoni and ripped several Edgar Degas sketches from their frames. They apparently tried, unsuccessfully, to take a Napoleonic flag out of its frame.

The entire episode lasted 81 minutes. Over the years, investigators from the FBI and the museum itself have pored over the details of where the thieves went, why they took the items they did, why they passed by other more valuable works.

There are a multitude of theories behind the thefts, none of which Amore would discuss publicly. It’s still an active investigation, and he takes heart that other thefts have ended with the pieces returned. The truth and the Vermeer, Rembrandts, Degas, Manet and other valuable works are still waiting to be discovered.

Amore asks that anyone with information regarding the stolen artwork to contact him: e-mail: aamore@isgm.org or theft@isgm.org. Phone: (617) 278-5114.

amilkovi@projo.com