Investigation into the alleged gang-rape of three tribal women and a minor girl at Viramgam near Ahmedabad on the night of October 18 has made no progress yet.
In the incident, the victims were also looted of cash and jewellery worth Rs 50,000. The accused are yet to be identified.
Deputy Superintendent of Police Girish Pandya said, "We are studying the modus operandi in similar incidents in the past and are hopeful of a breakthrough within two-three days.
"Gangs which are involved in such loot-and-rape cases move around, shifting their base, making it difficult to trace them," Pandya said, adding that Local Crime Branch and Special Operation Group were also taking part in the probe.
The victims, originally from Garbada in Dahod district, were working on a construction site of Narmada canal project.
They were sleeping in temporary tents near the site, about a kilometre away from Hansalpur village, when the incident took place.
The assailants, total seven, intimidated men and the children before raping the victims and fleeing with Rs 30,000 cash and silver jewellery worth Rs 20,000.