They were arrested on the charge of trespassing into the St Thomas Aided Higher Primary School in Bondantila near here on July 30.
Around 50 Sri Rama Sene activists had raided the school for 'forcibly' teaching Arabic and Urdu to students.
On a complaint from the school headmaster, three activists were arrested yesterday.
Meanwhile, the headmaster said that classes (in Urdu and Arabic) were being conducted for 40 students everySaturdayon the request of parents.
In a statement, D'Souza said he had asked the city police to be tough against groups trying to disturb peace and tranquility.
He also visited the school and spoke to students and teachers.