Aventura police and a hazardous materials squad from Miami-Dade County swarmed Aventura City of Excellence Charter School April 29 after two letters containing mysterious white powder were found. The letters were addressed to teachers, WPLG, ABC-TV channel 10, reported. The school was locked down for hours until field tests showed the powder was not harmful.

Read the story and see the video:

http://www.justnews.com/news/19322913/detail.html/

In a letter to parents on the school's website, Principal Julie Alm writes:

"The information contained in the letters was not directed to the Aventura City of Excellence School or to students who attend ACES. Based on the investigation of the responding agencies there is no threat to our students or campus."