A case has been filed with Banani police station in connection with the attack on Ashraful Alam, popularly known as Hero Alam.
His personal assistant Sujan Rahman Shuvo filed the case on Tuesday afternoon accusing some 15-20 unknown persons.
Till now, seven people have been detained in connection to the attack.
Hero Alom was subjected to a physical assault in Dhaka's Banani area shortly before the end of voting on Monday.
He later alleged that ruling party men had attacked him at Banani Bidyaniketan School and College polling centre in the afternoon with the intention of murder.
Alom later received treatment in the emergency department of Better Life Hospital in Rampura.
The UN office in Bangladesh has expressed concerns over the attacks on Hero Alam.
Meanwhile, the US also sought an investigation into reports of violence over attacks.
The US wants the investigation to be conducted "thoroughly, transparently, and impartially, and to hold the perpetrators of violence to account.”
