BUJUMBURA – Nine schools are being investigated in eastern Burundi after photos of the president 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.
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.
His decision to stand for another five-year term and his subsequent re-election sparked protests from opposition supporters who said the move was unconstitutional.
The BBC's Prime Ndikumagenge in the capital, Bujumbura, says the 234 pupils at Gahinga Secondary School in Ruyigi province were also prevented from sitting their end-of-year exams on Tuesday because they would not tell the authorities who had scrawled on the President Nkurunziza's photo.
The students were asked to write down the names of those who had defaced the books and the names of those who had encouraged them to do it.
"But they gave us blank sheets," local government official Aloys Ngenzirabona told the AFP news agency.
The picture of Burundi's president is alongside those of two former monarchs in books on human sciences for grades eight and nine, our reporter says.
Defaced pictures of the president were first reported in a school south of the capital last month.
Guillaume Kwizera, head of education in Ruyigi province, told the BBC the students would remain at home until the investigation into all nine schools was complete.
The authorities want to know if there a political motive behind the pupils' conduct.
More than 400 people have been killed in unrest since April 2015.