Guwahati, May 8 (IANS) Assam Chief Minister Tarun Gogoi on Sunday questioned the source of BJP's poll funding in the recent assembly elections during which, he said, the party had "spent money like water" while campaigning. "The amount of money involved in the BJP poll campaigning raises strong doubt on its source of funding. The party spent money like water and such a lavish campaign is unimaginable without strong corporate backing," Gogoi said in a statement here.