In a major breakthrough, the National Investigation Agency (NIA) has arrested a key conspirator in Bengaluru's Rameshwaram Cafe blast case, according to an official statement issued on Thursday.

Muzammil Shareef was picked up on Wednesday and placed in custody as a co-conspirator after NIA teams cracked down at 18 locations, including 12 in Karnataka, five in Tamil Nadu and one in Uttar Pradesh, it said.

The NIA, which took over the case on March 3, had earlier identified the main accused, Mussavir Shazeeb Hussain, who had carried out the blast.

It had also identified another conspirator, Abdul Matheen Taha, who is also wanted by the agency in other cases, the statement said.

"Both the men are on the run,” it added.

NIA investigations have revealed that Muzammil Shareef had extended logistic support to the other two identified accused in the case, involving an IED explosion at the cafe located at ITPL Road, Brookefield, Bengaluru, on March 1.

Several customers and hotel staff members were injured, some of them grievously, in the blast, which caused extensive damage to the property.

"Raids were conducted today at the houses of all these three accused as well as the residential premises and shops of other suspects,” the statement said.

Various digital devices were seized during the searches, along with cash, it added.

Efforts are on to nab the absconding accused and unearth the larger conspiracy behind the blast, the NIA said.