Dunleavy (89) was sentenced to ten years behind bars this week after being convicted of 36 charges of historical sexual abuse against nine boys.
The sexual offences took place between 1964 and 1991 while Dunleavy worked at four schools in Belfast, Newry and Armagh with the victims aged between seven and 14 at the time.
Before Thursday’s hearing Dunleavy was already behind bars after he was previously convicted on two separate occasions of sexual offences against children.
The Congregation of Christian Brothers has now confirmed to a solicitor acting for many of Dunleavy’s victims that he is still a member of the order.
Owen Beattie, of Owen Beattie Solicitors, said his clients are “rightly angered by the confirmation that Paul Dunleavy remains a member of the Christian Brothers”.
“There now needs to be a root and branch examination as to why Dunleavy, despite his criminality, has not been expelled from the Christian Brothers,” he said.
“The relationship between Dunleavy and the Christian Brothers needs to be interrogated against a background of serious sexual abuse.”
Mr Beattie said that after years of questions his clients “deserve answers”.
“We intend to actively engage with the keys players to get to the bottom of this scandal,” he said.
The Christian Brothers said it unreservedly apologises to the survivors of abuse perpetrated by Dunleavy.
“It is with shame that we acknowledge the damage done by Brother Dunleavy,” it said in a statement.
“The Christian Brothers fully recognise the terrible damage that was done to innocent children who should have been protected and respected. We are open to meet with any survivor who wishes to make contact with us.”