An IED blast was carried out by Maoists in in Jambhulkheda tehsil of Gadchiroli on May 1. (File)

The National Investigation Agency (NIA) is set to take over probe into the May 1 Maoist attack case in Maharashtra's Gadchiroli in which 15 security personnel and a driver were killed, a senior police official said on Saturday.

Gadchiroli Superintendent of Police Shailesh Balkawde said: "We have arrested eight Maoists so far in the case. The latest arrest was of Kailash Premchand Ramchandani, 34, on June 29. Two of those arrested are senior functionaries in the Maoist outfit."

"The NIA will take over the case in the next few days, just like it has done in cases in Chhattisgarh and other states recently," he added.

An IED blast carried out by Maoists in in Jambhulkheda tehsil of Gadchiroli on May 1 killed 15 policemen and a civilian driver. The impact of the blast created a large crater on the road.

Gadchiroli police had earlier arrested the Maoists' "western sub zonal chief" Nirmala Kumari and her husband Satyanarayan, who belonged to Andhra Pradesh.

On June 13, two more accused, Dilip Shriram Hidami, 22, and Parasram Mangaram Tulawi, 28, were arrested from Kurkheda taluka of Gadchiroli district. On June 23, three more Maoists were arrested.