A letter containing a mysterious white powder was sent to Hillary Clinton's campaign

Updated: 



Police in New York are investigating an envelope containing a white powdery substance that was sent to Hillary Clinton's campaign, forcing an office to be evacuated.

A spokesman for the New York Police Department said the envelope was found at Clinton's Manhattan office, where mail is received, on Friday evening. It was then taken to the 11th floor of her Brooklyn headquarters.

Hillary Clinton
(Matt Rourke/AP)

The discovery of the suspicious substance caused that floor to be evacuated. There were no reports of illness or injury.

It was not immediately known what the substance is, or whether it is harmful.