Three persons were detained on Monday for interrogation in connection with the bomb blast at a rehabilitation centre in Kandhamal district which left one dead.
They were being interrogated for their suspected Maoist links, Kandhamal SP Praveen Kumar said.
Seizure of four guns from the site of the blast led to the suspicion that they had Maoist links, he said.
The identity of the person killed in the explosion on Sunday has not been ascertained so far, while the injured has been identified as Patrasen Mallick of Batikola village.
The person who died in the blast did not belong to Batikola village and had arrived at the rehabilitation centre at Nandagiri barely five days ago, he said.
A forensic team visited the spot to determine the nature of the explosive used in making the bomb.