Acting on a tip off, Amrendra Singh was arrested this evening with three others in Gomti Nagar area, a STF release said.
The release claimed that during interrogation, the accused said Shukla was attacked to terrorise him to get their some work done for which "negotiations" had earlier failed.
Shukla was attacked and left injured by unidentified persons with baseball and hockey sticks about 200 mt away from his home while he was on his way to office, it said.