I read the same thing, but can't substantiate it, and those who know are keeping quiet.
Still, Trayvon had nonviolent behavioral issues in school, and on the day he was killed, he had been suspended for 10 days from Dr. Michael M. Krop Senior High School in North Miami-Dade.
Read more here: http://www.kansascity.com/2012/03/22/3507783/trayvons-parents-paint-portrait.html#storylink=cpy
Hope that helps.
Try this, it came from his own brother on Facebook 5 days before he was shot for ambushing and beating Zimmerman:
http://www.examiner.com/charleston-conservative-in-charleston-sc/trayvon-martin-s-ten-day-suspension
JC