The police  arrested an alleged Lashkar-e-Toiba (LeT) operative connected with the  Mecca Masjid blast, officials said on Thursday.
Nayeem alias Sameer is one of four suspected LeT cadres caught by the Border Security Force (BSF) near the Bangladesh border in April while trying to sneak into West Bengal.
He was brought to Hyderabad from Mumbai and was remanded to judicial custody for 14 days.
During a narco-analysis test, Sameer reportedly told Mumbai police that he had transported RDX to Hyderabad, officials said.
This was the second arrest by the Special Investigation Cell (SIC) of the city police, which is probing the May 18 bomb attack in the mosque that left 11 dead and over 50 injured.

Fake passport
The police also arrested Shoaib Jagirdar, a close associate of Sameer, from Jalna in Maharashtra on May 25. The city police found that he tried to help Sameer to obtain a passport with a fictitious.
Police are now trying to nab three others who unsuccesfully tried to obtain a passport for Sameer, a SIC source said.