Two persons in a fibre glass boat, who arrived near Dhanushkodi from Sri Lanka, were arrested Tuesday, Coast Guard officials said.
The two claimed they belong to Madurai district in Tamil Nadu and that they had come from Lanka, the officials said.
Interrogations were on to find out whether they had dropped any person in Lanka or taken any refugee from here to the island nation and returned, they said.
A case has been registered, they added.