Unidentified gunmen shot dead four persons of a family and injured one at Ziaguri village in Assam's violence-hit Kokrajhar district on Friday night around 11 pm.
The fresh violence happened a day after a 16-year-old boy was killed and two others were injured in clashes in the city.
Rumour-mongering has largely affected the process to calm down the situation and bring peace in troubled Manipur.
Two of the people arrested are mafia members who are "wanted on a number of murders" in India.