Envelopes containing suspicious powder were sent through the mail to at least seven locations in Manhattan, primarily Wells Fargo banks, police officials said.

"This is a reminder that you are not in control," said a message that arrived with the envelopes. "Just in case you needed some incentive to stop working we have a little surprise for you. Think fast you have seconds."

Several samples tested negative -- evidently containing corn starch, police said. Later, all the powder samples were determined to be non-toxic, The Associated Press reported.

The receipt of the white powder prompted evacuations at bank branches, police told the AP, but caused no injuries.

http://abcnews.go.com/US/day-protest-banks-white-powder-envelopes/s...