The victims were on their way to take part in a fair organised by Jain community in Maxi town on the occasion of Rangpanchmi festival, a sub-inspector at Dewas Kotwali police station said.
The deceased have been identified as Virendra Kumar Jain (45), Sanjay Jain (38), J K Jain (45) and Jinesh Kumar Jain (45), he said.
The injured person was referred to Indore for treatment.
The bodies were handed over to their relatives after the autopsy, police said, adding that a case has been registered in this regard.