In Boston on March 18, law enforcement officials announced that they have identified the perpetrators in the $500 million art heist at the Isabella Stewart Gardner Museum in 1990. Investigators have been baffled for decades over the theft, one of the biggest art crimes in history.

A decade ago, an attempt was made to sell some of the 13 artworks, including three Rembrandts, a Vermeer, a portrait by Edouard Manet, and sketches by Renoir. But the location of the stolen masterworks is still unknown.

“The FBI believes with a high degree of confidence in the years after the theft the art was transported to Connecticut and the Philadelphia region and some of the art was taken to Philadelphia where it was offered for sale by those responsible for the theft. With that confidence, we have identified the thieves, who are members of a criminal organization with a base in the mid-Atlantic states and New England,” stated Richard DesLauriers, special agent in charge of the Boston office of the FBI.

Officials are seeking help from the public and will be launching a massive public awareness campaign that will stretch beyond New England. Among the exposure tactics will be a dedicated FBI website, video postings on FBI social media sites, digital billboards, and a podcast.

There is a $5 million reward for information on the whereabouts of the missing art. The statute of limitations has run out on the robbers, and they might be granted immunity for other charges, such as possesing the stolen paintings.

The FBI can be contacted with leads at 1-800-CALL FBI, or tips may be submitted online at https://tips.fbi.gov.

Twenty-three years ago, two robbers dressed as policemen tied up security guards at the Boston museum, and then disappeared with the prized artwork, including Rembrandt's only known seascape.

One of the guards on duty that night may be under increased scrutiny, the Boston Globe reports.

Since the investigation is ongoing, the identities of the suspects have not been released by authorities.