Santram and Munnaram, both residents of Sitapur, were arrested yesterday on a tip off.
During interrogation, the duo said that one Babadur, a native of Nepal, is kingpin of their gang which used to steal such idols from the state and sell them at high rates.
The 'ashtadhatu' idol is worth about Rs 2.5 crore and the two were in the state capital to find buyers for it, they said.
Ashtadhatu is an alloy of eight metals - gold, silver, copper, tin, lead, zinc, iron and antimony.