St. Petersburg's Hermitage Museum announced the disappearance of 221 exhibits from storage on July 31, following a routine check.
"This afternoon, police received a phone call from an unidentified man who said that the icon, the Synaxis of All Saints, was lying in a dustbin near the police office specializing in antiques," the police source said, adding that the late 19th century icon had yet to be identified by experts.
The Hermitage said earlier that the missing items were pieces of Russian jewelry, mainly enamel work, with an estimated value of 130 million rubles ($4.9 mln). The museum's director said Tuesday the theft was probably carried out over several years and could not have happened without the collaboration of Hermitage staff.
The Russian section of the Hermitage contains over 300,000 works of art from Russia's thousand-year history. The museum, comprising six buildings, has one of the world's largest art collections.
The museum's press service refused to confirm that the icon discovered by police was from its collection.
"We have received no information about this," the museum spokesman said.
Police have asked St. Petersburg residents to help in tracking the Hermitage valuables, and have offered guarantees of anonymity.
The museum has published the full list of missing items on its official Web site, http://hermitage.museum.ru.