Secondly, most of the schools are burnt only when students are somewhere else.
Thirdly, the arsonists mostly escape successfully even when they act in broad daylight at heavily guarded places.

But most importantly, BaretaNews has 'uncovered' a very useful clue.
The news site reports that one of its reporters overheard a bitter exchange of words between a police commissioner and an unnamed principal of a boarding school in Buea last Thursday.

The two guys were reportedly quarrelling over the payment of police officers to guard the unnamed school.
The reporter said the  principal refused to pay the routine FCFA 15000 to the commissioner.
The lady maintained the officers had been sleeping instead of watching over the institution.

This suggests, according to BaretaNews, that  men in uniform could be part of the chain of arsonists in Southern Cameroons.

Even so, it's difficult to conclude at this level. Most of the schools burnt down have been defying ghost town and no-school-resumption calls. Others are believed to have received warnings from anonymous sources, cautioning against school resumption.