Correctional Services spokesman Manelisi Wolela has denied allegations that student leader Mcebo Dla.
Two Gauteng leaders of the teacher union Sadtu were acquitted on charges of malicious damage to property and assault in the Vereeniging magistrate's court yesterday.
Magistrate Ebrahim Makda found Sam Nengwekhulu and Moses Senye not guilty of the charges related to the public sector strike in June last year.
Senye, Gauteng central regional chairman, and Nengwekhulu, Ennerdale branch chairman, allegedly assaulted Clare Lucas, the principal of St George's Primary School in Ennerdale, two pupils and the school's cleaner on June 4.
The courtroom was packed with union members and supporters who wore T-shirts bearing the face of ANC president Jacob Zuma.
Soon after the two were acquitted the packed gallery cheered, ululated and chanted slogans.
Others exchanged hugs with Nengwekhulu and Senye and lifted the two shoulder-high.
All state witnesses, except Lucas, withdrew.
Defence advocate Gys Rautenbach argued that the state had a weak case and that Lucas contradicted herself.