According to the FBI website:
During the week of May 7, 2012, over 20 letters containing white powder were received by early childhood development centers, elementary schools, and an aerospace-related business.The most recent batch of letters contained this Scooby-Doo-rich gem:
|Try singing this to the tune of the Scooby Doo song. It works better than you might think.|
via Boing Boing.