TIM KELLY PHOTO | District Attorney Tom Spota, flanked by Shelter Island Police Chief Jim Read (left) and Southold PD Chief Ty Cochran, speaking to reporters during Friday's art theft press conference.

Who is he? Who is the mystery man who investigators say played a critical role in breaking the case of the theft of more than $500,000 in artwork and other valuables from unoccupied East End homes during the winter?

He’s a North Fork art dealer, said District Attorney Tom Spota, who declined to give the man’s name. Mr. Spota said the art dealer was contacted three times by Angel Giovanni Palencia, 24, of Medford, trying to sell the stolen art. Mr. Palencia was indicted Friday on felony burglary and grand larceny charges connected to a string of art thefts in Southold, Shelter Island, Southampton and East Hampton. He is being held on $500,000 bail.

The North Fork dealer grew suspicious, and after he learned through a fellow dealer that some of the art was reported stolen in East Hampton, he contacted the Southold Town Police.

Southold Police arrested Mr. Palencia on April 6 after recording a conversation between him and the art dealer, the district attorney said during a Friday morning press conference at the County Criminal Court Building in Riverside.

Mr. Palencia is alleged to have taken a painting and a silver tea set from a house on Soundview Avenue in Southold, and a painting and a stamp collection from a Rocky Point Road residence on Shelter Island.

Flanked by samples of the stolen art recovered by investigators and joined by area law enforcement officers, the DA said Mr. Palencia had admitted to the thefts, but said he was working on his own.

But police think otherwise.

“Nobody believes that this defendant was working by himself,” said Mr. Spota. “He certainly wasn’t running around to houses in East Hampton and looking in windows.”

Police said there’s no evidence of forced entry at any of the burglarized homes and the property owners said the windows were locked and the alarms set.

Mr. Spota stopped short of describing the crimes as part of an organized art theft ring. He did say, “The police are looking at a number of individuals they believe may have participated.”

Mr. Palencia is accused of taking 30 works of art and other valuables worth between $550,000 and $600,000 during January and February.

The defendant is no stranger to the East End, the DA added. He’s worked as a carpenter on Shelter Island and for a painting contractor on the North Fork. While working on Shelter Island, he had knowledge of an extra house key kept outside which “he found to be very handy,” said the DA

Southold police said Mr. Palencia, an undocumented worker, was arrested on a DWI charge in Southold several years ago.

Investigators said some of the stolen artwork is still missing, but they’ve also recovered pieces that have not been reported stolen. Southold Police Chief Ty Cochran said the owners are most likely second-home owners unaware of the thefts.