Gita, mother of one Vikrant, who was also involved in the attack on the BJP MLA, was arrested yesterday, SHO Rojent Tyagi said.
The three accused Vikrant, Kapil and Pradeep are absconding, the SHO said.
Kapil Dev Agarwal sustained eye injuries after three youths threw red chilli powder on him while he was meeting people at his office on September 12.