The National Investigation Agency (NIA) on Sunday carried out raids at three places at Kasaragod and Palakkad in Kerala in a probe connected to an Islamic State module case.
NIA is questioning three suspects who are believed to have links to some of the people from the state who left for Syria and Iraq to join the IS. Two of the houses raided are in Kasaragod while one is in Palakkad.
The probe agency also recovered incriminating evidence from the houses raided on Sunday.
Mobile phones, SIM cards, memory chips, pen drives and handwritten notes in Arabic and Malayalam were among the material recovered in the raids.
Reports say that the NIA also recovered DVDs and books of controversial preacher Dr Zakir Naik.
The NIA is probing the disappearance of 21 people from the state in May 2016. They are believed to have travelled to Syria and Iraq to join the barbaric terror group.
While 17 of them were from Kasargod, four were from Palakkad. Among them were six women and children.
Reports say that some of them may have died in the coalition attacks on the terror group that led to its fall.
The NIA raid came seven days after an Islamic State splinter group, National Thowheed Jamaath (NTJ), targeted three churches and three hotels in Sri Lanka killing 253 and injuring around 500. Among the dead were 11 Indians.
A total of 106 suspects have been arrested following raids at multiple locations across Sri Lanka. In one of the raids in Eastern province, 15 people, including women and children, were killed when terrorists fired at security force personnel and blew themselves up.