Sri Lanka's Terrorism Investigation Division has arrested 38 people over alleged links to 'Ava group' in Jaffna, the minister of law and order, Sagala Ratnayake was quoted by Adaderana as saying.
Mr Ratnayake said a further 8 individuals are currently under investigation and the officers are seeking their arrest.
The arrests have been severely criticised by families who argue they took place illegally.
On Monday families lodged a complaint with Sri Lanka's Human Rights Commission stating it was illegal to arrest the men under the Prevention of Terrorism Act (PTA) then take them to Colombo and charge them with robbery.
Civil society groups have questioned the government's narrative of the group, whilst locals have accused the Sri Lanka military of being responsible for the group's activities.
Responding to the reports, the state minister of defence, Ruwan Wijewardena was quoted by Adaderana as saying, "claims that the Ava Group has connections with the army cannot be completely ignored."