"Ashish Chandel, a constable with Indore Lokayukta police turned out to be the conspirator who got 2.772 kg Class 2 explosive and 25 detonators placed in a room of a boys' hostel in Ujjain on Friday," MP Anti Terrorist Squad Inspector General of Police Sanjeev Shami told reporters here.
Chandel placed the explosive in the room with the help of one Sushil Mishra, a private security agency staffer, who has also been detained.
However, he did not divulge other details of the case saying investigations were still on.
On March 19, Ujjain police recovered the explosive in a sealed packet in a bag from the hostel and sent it to a chemical testing laboratory.
Besides the bag, a mobile handset and some identity cards were also found in the room of Atishay Hostel situated near bus stand under Nankheda police station area of Ujjain.
The hostel owner had got suspicious and informed police when the occupant of the room did not return after being out for hours.
After investigations, we found that Chandel who had been earlier posted at Ujjain had hatched the conspiracy to frame his enemies, the IG said.
He said that Mishra, accomplice of Chandel had earlier worked with a mining firm at Ashok Nagar district from where he had acquired the explosives.
The recovery of explosives had sent police into a tizzy as the Simhastha-Kumbh Mela in which a sea of devotees throng is scheduled to start next month in Ujjain. Police had studied the case from all angles before reaching a conclusion, a officer said.