The incident occurred on the intervening night of Saturday and Sunday in the Wagle Estate area of the city.
Police said one of the accused suspected that the victim, Ramawtar Dhobi, was abducting a minor girl, following which he raised an alarm and attacked Dhobi.
Dhobi was thrashed by at least ten people, which resulted in his death, an official said.
The arrested accused are identified as Atiq Khan, Mohasin Shaikh, Afsar Vasta, Harish Solanki, and Mohammad Ansari, he said.
A hunt is on to trace other accused involved in the crime.
A case has been registered under various sections of the Indian Penal Code and the Maharashtra Police Act.