Extensive use of acid bottles during the communal clash in Dhule may have contributed to the spread of violence, said sources.
While more than 200 people were injured in the riots on Sunday, five were killed in the subsequent police firing.
The additional director general of police (law and order) is likely to submit a report on the incident on Saturday.
According to sources, the fight started over the payment of bill at a restaurant in Machchi Bazaar. A section of people lobbed acid bottles on passersby who then retaliated, leading to mob violence.
Initial investigation has revealed that the acid bottles were kept in a godown adjacent to the restaurant. The rioters, who allegedly knew the storage area, then used them to attack people.
According to sources, the police have identified the hooligans who started the clash on the basis of video footage obtained from local cable television operators. They are presently absconding.
Deven Bharti, inspector general of police, law and order, said that the curfew in Azad Nagar was lifted between 11am and 1pm on Thursday.
No untoward incident was reported during that period. Prohibitory orders, banning the assembly of more than five persons continued in the rest of the township.