New York City's Metropolitan Opera was forced to cancel its Saturday afternoon performance of Guillaume Tell after an audience member sprinkled an unidentified powder, which police believe was cremated ashes, into the orchestra pit.
New York City Police officials said witnesses had heard a man say he was at the opera to spread the ashes of his mentor.
"An individual from out of town ... indicated that he was here to sprinkle ashes of a friend, his mentor in opera, during the performance," John Miller, deputy commissioner for intelligence and counter-terrorism told reporters.
The Met said on its Facebook page that it also cancelled the Saturday evening performance of L'Italiana in Algeri, while police investigate the incident which happened in the second intermission.
There were no reports of any injuries or any bad reactions to the substance, though the theatre was evacuated and the New York Police Department dispatched a special unit to investigate, Officer Tiffany Phillips said.
The suspect, a man who was not identified, had fled the scene and no arrests have been made, Phillips said.
Met spokesman Sam Neuman told the New York Times that no one had been injured, but that, "As a safety precaution, the Met cancelled the remainder of the performance to err on the side of appropriate caution."
The Metropolitan Opera has seen other bizarre episodes in the past, including one in 1988 when a patron died during a plunge from the top balcony during the intermission of a performance of Macbeth.