Nine schools are under investigation in eastern Burundi after photos of President Pierre Nkurunziza were defaced in text books.
More than 230 pupils were suspended on Monday for refusing to own up to the defacement of 27 books at their school.
Mr Nkuruziza has been in power for a decade and has resisted calls to step down.
Eleven students in other provinces are already being prosecuted for insulting the president by defacing his photo, punishable by five to 10 years in jail.
Burundi has experienced unrest over the last year triggered by President Pierre Nkurunziza’s third term in office.