A Salvador Dali painting stolen last week from a New York City gallery was mailed back in pristine condition, police said on Friday.

Glimmers of hope had been raised earlier this week when the gallery received a brief email message by an unknown person, saying the 1949 ink and watercolor "Cartel de Don Juan Tenirio" is "on its way back to you already," police said.

The package was mailed from a location in Europe, and bore a phony sender name and address, according to Deputy New York Police Commissioner John McCarthy.

A spokesman for the gallery, which opened just this year on Manhattan's fashionable Upper East Side, declined to comment.

A second police source speculated that publicity surrounding the theft had complicated efforts to sell the painting on the black market.

Police detectives, including the department's in-house art expert, Detective Mark K. Fishstein, took possession of the painting from postal inspectors at John F. Kennedy International Airport when it arrived in New York on Thursday.

It was returned on Friday to the gallery, where it is being authenticated, McCarthy said.

Last week, a man visiting the gallery removed the painting from a gallery wall, placed it in a shopping bag, and walked out of the building.

Fishstein, the Brooklyn-born son of two antiques dealers, became the department's "art cop" in 2003 after he caught the attention of his superiors as a young patrol officer, McCarthy said.

Fishstein had been called to the apartment of an Upper East Side woman who had been found dead. His sergeant had just finished an inventory of the apartment's valuables when Fishstein suggested police secure the painting on the wall.

"Why?" his sergeant asked.

"It's an original Picasso," Fishstein replied.

In 2008, Fishstein arrested a couple who had stolen a $100,000 Andy Warhol print of Chinese communist leader Mao Zedong from a frame store.