Bodies of the victims, both students of an engineering college in Lonavla, were found on April 3.
Police have also announced an award of Rs 50,000 for any information about the murder.
The victims were found to have been hit on the back of their heads with a blunt object.
Pune district police had formed multiple probe teams earlier, but could not crack the case.
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An award of Rs 50,000 had been announced for providing information about the culprits, he told PTI.
Vishwas Nangare-Patil, Inspector General (Kolhapur Range), said the police were investigating various angles and had questioned several people.
Meanwhile, parents of the boy said they were going to meet the Chief Minister and demand speedy investigation.