Police in New York City say three letters aimed at scaring mailroom employees at Citicorp and News Corp. were filled with a white powder believed to be cornstarch.

NYPD spokesman Paul Browne said the letters were mailed to The Wall Street Journal, Fox News and Citicorp. They arrived Tuesday. Seven other similar letters arrived at various banks on Monday.

The letters Tuesday were kept in the third-level basement, and the News Corp. building on Sixth Avenue was not evacuated.

The letters contained a threatening message that said “This is a reminder that you are not in control” and “Happy May Day.”

(Source: MyFoxNY)