Acting on a tip-off, the SID along with the State Intelligence bureau seized 17 kg of explosives and 141 electric detonators kept concealed in a house in Melapalayam area, state DGP K Ramanujam said in a statement here.
Tasim, Katta Shahul, Kutty alias Noorul Hameed, Samsu and Bismi were arrested in this regard, he said.
The SID has been set up by Chief Minister Jayalalithaa to probe the murders of BJP state General Secretary V Ramesh in Salem on July 19 and Hindu Munnani State President Vellaiyappan in Vellore last month.
He said the package was hidden in a house without disclosing the nature of the contents to the owner.
The five wanted in connection with the murders and earlier bomb incidents -- Abu Backer Siddiq, 'Police' Fakruddin, Bilal Malik and Panna Ismail -- may be in possession of explosives and public should not give them accomodation, he said, adding "people are requested to inform about any other suspicious persons or suspicious materials".