With militant outfit ULFA denying its involvement in Thursday's serial blasts in Assam, the police said it was the handiwork of jehadi outfits, including Bangladesh-based HUJI.
"The needle of suspicion points to jehadi outfits who are behind subversive activities in the state," IGP (Special Branch) Khagen Sharma told PTI here.
The jehadi elements, including Bangladesh-based HUJI, could be working in groups or individually, the senior police official said the modus operandi pointed to their involvement.
"While investigation will go on, the police have been zeroing in on Islamic fundamentalist forces which of late have been active in the state and the region," he said.
Six suspected jehadi militants were recently killed by the security forces in Dhubri district.
Pointing out that several ISI-backed militants have been arrested in the past, Sharma said their interrogation revealed that their activity was on the rise.
The police official, however, denied there was intelligence failure on the part of the authorities.
Kamrup (Metro) Deputy Commissioner Prateek Hajela also suspected the involvement of HUJI militants.