A team of National InvestigationAgency and forensic experts on Friday visited the sites of February 21 twin blasts at Dilsukhnagar, as part of the ongoing probe.
"Forensic experts of Gujarat FSL visited the scene along with NIA officials," police said.
Hyderabad branch of NIA has already lodged two FIRs in the case. The first FIR is about 'unknown persons' who caused blast by Improvised Explosive Device at 72 Bus stop near Venkatadri Theatre, while the second deals with blast at Mirchi Shop at Rajiv Chowk.
The NIA website, where FIRs have been uploaded, also carries the photos of Yasin, Riaz and Iqbal Bhatkal as wanted.