Description:Sao Paolo's carnival judges were just minutes away from announcing the Brazilian city's champion samba troupe when violence flared. A man allegedly from the Imperio de Casa Verde samba troupe which risked being downgraded from the elite group of schools leapt a security fence and tore up the results. The incident ignited a series of other attacks as upset supporters of other samba groups invaded the judges' area, overturning chairs and tables.(0:44)