The Seminole County Sheriff's Office says John Carnduff Stewart of Melbourne Beach emailed Sanford Police Chief Bill Lee on Friday, saying Lee and his family should be killed. Melbourne beach is nearly 70 miles south of Sanford.
The sheriff's office says Stewart has sent threatening emails previously, including threats to Penn State University assistant football coach Mike McQueary.
Stewart was placed on electronic monitoring as a condition of his $10,000 bond.
Lee temporarily stepped down as chief amid national outrage over the investigation. The neighborhood watch captain, George Zimmerman, has not been charged in Trayvon Martin's death.
