Raju Vishwakarma was arrested after police kept a close watch on his activities, SP Ravi Shanker Chavvi said, adding he had been sent to jail.
On Friday, former BSP legislator Suresh Tiwari alleged he was receiving threat calls demanding Rs 25 lakh.
"I have received threat calls on my mobile on December 15, 16 and 17 and the caller demanded Rs 25 lakh," Tiwari said.