Notorious art thief Myles J. Connor Jr., whose outlaw life has taken him from rock ’n’ roll fame to federal prison, was nowhere near the Isabella Stewart Gardner Musuem on the night of the legendary $300 million art heist.

But on several occasions, Connor, 65, has told the Herald that he cased the Hub museum and believes some of his associates are behind the March 18, 1990, theft.

Connor, the son of a Milton cop, was first linked with efforts to recover the stolen masterpieces in 1997. At the time, Connor was serving a 15-year sentence in a Pennsylvania federal prison for interstate trafficking in stolen antiques and drug charges.

“I know emphatically and beyond any doubt who stole the art,” Connor once told Time magazine, ABC News and other media outlets. It was a repeat of a tale Connor had told the Herald many times as well.

In those interviews, Connor described how he and “flim-flam artist” Robert A. “Bobby” Donati cased the Italian palazzo-turned-museum during a visit in 1974. (See “Meet the Suspects” for March 29.)

“I took a walk through the place and saw what was there,” Connor said. Connor added that Donati was intrigued by an item that was later stolen - the golden eagle atop a Napoleonic flagstaff.

Connor joined briefly with a shady Randolph antiques dealer, William P. Youngsworth III, in offering to help “broker the return” of the art to baffled museum and FBI officials.

Since then, Connor severed ties with Youngworth, whom he accuses of embezzling $2 million worth of art and antiques that Connor says he acquired legitimately during his colorful career.

Connor’s career as an art thief began in 1966 for a robbery at the Forbes Museum in Milton. During a pursuit, he shot and wounded state police Cpl. John J. O’Donovan.

He was paroled in 1972 but re-arrested in 1974 for stealing several artworks by Andrew Wyeth from the Woolworth estate in Monmouth, Maine. He pleaded guilty but avoided jail by famously arranging the return of a $1 million Rembrandt, ‘Portrait of Elizabeth Van Rijn,’ which was stolen from the Museum of Fine Arts in broad daylight.

Connor, a guitarist, stayed out of prison and found time to jam with the rock group Sha Na Na. The regional press dubbed him the “president of rock ’n’ roll.” In 2003, Massachusetts-born Hollywood mogul Peter Guber bought the rights to his life story.

In 1981, a jailed hit man, Thomas Sperrazza, turned state’s evidence and accused Connor of engineering the 1975 screwdriver killings of two 18-year-olds, Susan C. Webster and Karen Spinney - both witnesses to a murder in Roslindale linked to a Connor associate.

Connor was convicted of ordering and directing the murders, but his verdict was overturned on a technicality in 1984 by the Supreme Judicial Court.

Connor was then retried in the teenagers’ murders in 1985, but jumped bail hours before he was found innocent by a 12-person jury. He was quickly caught and given a year in prison on the bail-jumping charge.

At the time, Connor’s name also surfaced in connection with the 1984 theft of the Massachusetts Bay Colony Charter and its beeswax seal from the basement of the State House.

The historic artifacts disappeared from a virtually unguarded glass case in the State House basement. The charter page was found seven months later in a raid at the apartment of a Dorchester woman who had ties to Connor. Several boxes of Connor’s personal papers and books were reportedly seized in that raid, which also turned up more than $200,000 worth of Oriental rugs, antique firearms and narcotics.