NIA can now take over the investigation from the Tamil Nadu police.
Sections of the stringent anti-terror law UAPA have been invoked in the Coimbatore car blast after 75 kg of explosive raw materials were seized from the residence of the accused, including of 25-year-old Jameza Mubin who died in the blast, during search operations in the last two days.
Unlawful Activities (Prevention) Act is a scheduled offence under the National Investigation Agency Act. The probe agency can now take over the investigation from the Tamil Nadu police.
The state police were investigating terror links into the gas cylinder blast in a car on Sunday after huge quantities of explosives were found at the victim's house.
The blast, near a temple in Coimbatore, killed Jameza Mubin, who was questioned by the central anti-terror agency over alleged ISIS links in 2019, police said.
The engineering graduate's associates are being interrogated, and more arrests are likely, sources said.
Mubin was driving with two open cylinders and one of them exploded, police said. A search of his house later in the day led to the recovery of "low-intensive explosive material", including potassium nitrate, aluminium powder, charcoal, and sulphur - used for making country bombs.
Those seemed to be meant for "future plans", said Tamil Nadu police chief C Sylendra Babu on Sunday.
Besides, vehicle nails, marbles, and other things were found in the car that exploded and those are being examined by the forensic department, said the top officer.