"One FSL has given the report that RDX was used in the Delhi High Court blast," Union Home Secretary R K Singh told PTI.
"The investigation is progressing in the case and a blow by blow account cannot be given," Singh said on the sidelines of an event here.
This report is said to be received from the Gujarat Forensic Sciences Laboratory (GFSL), according to sources.
Fifteen people were killed and over 70 others injured in the blast that occurred outside gate number 5 of the court complex.
Opinions of various forensic labs have been differing over the explosive used in the blast.
While a few have suggested the use of Nitrate-based explosive material, forensic experts from NSG had suggested a mix of Ammonium Nitrate with PETN.
The National Investigation Agency (NIA) is probing the blast case even as a number of e-mails were received by the investigators claiming responsibility for the act of terror.
Published 28 September 2011, 07:50 IST