Samples of a tea found in a pot in the Vhanmore residence have already been sent for forensic analysis, and the police are also trying to find out what poison was used and where Bagwan got it from, officials said.
The victims, which included a 70-year-old woman, her two sons and their families, were found dead in their residences in the Mhaisal village in Miraj on Monday.
Police have arrested 13 people on charges of abetment of suicide of nine members of a family of two brothers in Maharashtra's Sangli district, an official said on Tuesday.