MANCHESTER, Conn. - Federal authorities on Thursday searched the home of an alleged mobster who has been questioned repeatedly about the notorious Gardner Museum heist, an indication that investigators are sharpening their probe into the decades-old, mysterious theft of priceless artwork.
Investigators with ground-penetrating radar and specialized dogs descended on the Frances Drive home of Robert Gentile by 6 a.m., said his lawyer, A. Ryan McGuigan, on Thursday morning. McGuigan also said that a ferret was used in the search and that authorities had a warrant allowing them to search all of the property for weapons. He learned later that two guns were found.
The search on Thursday follows one investigators had conducted at Gentile’s home and in a shed after his arrest in February on drug charges, and McGuigan questioned Thursday whether authorities were covertly expanding their investigation to include the search for the artwork.
Authorities would not comment on the search Thursday, but have said they believe that Gentile, an alleged member of the Mafia, could have information about the Gardner heist. He has been held without bail since his February arrest.
McGuigan said that his client has cooperated with authorities and has even testified before a grand jury, but that he denies any knowledge of the theft or of the paintings. He asserted the arrest of Gentile on drug charges and the following searches have been part of a strategy to harass and pressure his client into providing more information, though he maintains he knows nothing more.
“It’s all a ruse,’’ McGuigan said in an interview. “It would appear that they weren’t looking for firearms at all, that they were looking for something else . . . and we all know what they are actually looking for, and they are looking for the paintings.’’
Authorities could be seen leaving the home at around 5:30 p.m., some of them with evidence markers, lights, metal detectors, and boxes. No one answered the door at Gentile’s home. Two cars were in the driveway, and the backyard was open.
Residents in the tranquil neighborhood said the day’s events caused quite a stir.
“It was like something from ‘Men in Black,’ ’’ said Linda Gilbert, 50, who said she woke up to see unmarked law enforcement cars and vans with tinted windows parked along the street.
The theft at the Isabella Stewart Gardner Museum, in Boston’s Fenway neighborhood, remains one of the most scandalous thefts in art history and perhaps the most sensational in Boston. The museum theft occurred early on March 18, 1990, when the city was still recovering from St. Patrick’s Day festivities. At least two men dressed as police officers conned their way into the museum, saying they had received a call of a disturbance.
Once inside, they bound the security guards with duct tape and handcuffs in the basement. From there, they spent 81 minutes in the museum, stealing some of its most valuable works: 13 masterworks in all, including three by Rembrandt and five by Degas. The case has become a priority for the US attorney’s office and the FBI in Boston since the arrest last year of fugitive James “Whitey’’ Bulger.
Authorities and the museum have offered a $5 million reward, along with anonymity and immunity to anyone with information, for the artwork, but to no avail. The pieces of art would be virtually impossible to move even on the black market because of the high-profile investigation, authorities have said.
Last fall, a Worcester man with a history of thefts said the FBI searched his home, even punching holes in the walls as they looked for artwork, but he said they found nothing.
Authorities have also searched homes in Dedham and in Maine in recent years based on information provided by convicted murderer Robert Beauchamp, who said that an old friend confided in him that he was involved in the heist, before the friend died of a cocaine overdose. Officials have said, however, that Beauchamp’s information did not result in any breaks in the case.
On Thursday, the FBI referred questions on the new search to the US attorney’s office in Connecticut, which is prosecuting Gentile on the drug and gun charges. Officials from that office would not comment.
The Gardner Museum released a statement Thursday saying it would not comment about the Gentile case, except that “the Museum continues to offer a $5 million reward for information leading to the recovery of the artworks in good condition.’’
“Anyone with information about the theft, the location of the stolen artworks, and/or the investigation, should contact the Gardner Museum,’’ the statement said.
At the museum Thursday afternoon, several patrons expressed hope that the investigation would lead to the recovery of the famous works. “It has been the great mystery of [Boston],’’ said Wendy Swart Grossman, a Brookline consultant and writer. “It left huge gaping holes in the collection and it’s a huge story.’’
Authorities have suspected everyone from low-level hoodlums to established con men and art thieves, Irish Republican Army gun-runners to a California screenwriter, and some of Boston’s most notorious organized crime figures.
Gentile is allegedly a member of the Mafia with connections to a Philadelphia crew that ran rackets in Boston. He has also been connected by authorities to notorious former New England Mafia boss Francis “Cadillac Frank’’ Salemme.
According to authorities, Gentile was introduced to the Mafia by capo Robert Luisi, who was from Medford and had ties to the Philadelphia crew. Luisi is serving a lengthy prison sentence on murder and drug convictions and has reportedly been cooperating with authorities in recent years. Prosecutors have said in court that Luisi has implicated his former associates, including Gentile, in other crimes.
Gentile was arrested in February on charges of selling prescription painkillers to a man who was cooperating with the FBI. He was indicted on new charges in April after authorities found guns and silencers during a search of his home. He faces at least 10 years in prison on each gun charge because he has a previous gun conviction.
His lawyer, McCuigan, suspects authorities are trying to levy more charges to “torture’’ his client into talking, and he questioned the need for the search Thursday after one was already completed.
“This case comes down to the fact that this guy sold his own painkillers to some kid who was working for the FBI, so they could search his house,’’ he said.
Globe correspondents Patrick D. Rosso and Colin A. Young contributed to this report. Milton J. Valencia can be reached at MValencia@globe.com. Follow him on Twitter @MiltonValencia. Martine Powers can be reached at firstname.lastname@example.org. Follow her on Twitter @martinepowers.