Special Judge L L Yenkar also held the trio--Yogesh Raut, Mahesh Thakur and Vishwas Kadam--guilty of robbery, misappropriation of property (possessed by the deceased) and criminal conspiracy.
The court would hear arguments on the quantum of sentence tomorrow.
The software engineer from an IT firm in Kharadi was kidnapped on the evening of October 7, 2009 from Kharadi bypass, when she was waiting for transport to go home.
Two days later, the 28-year-old techie's body was recovered from Zarewadi forest area in Khed tehsil of Pune district.
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Police probe later led to the arrest of four persons including one Rajesh Chaudhari, who later turned an approver in the case.
Special Public Prosecutor Harshad Nimbalkar said Chaudhari was acquitted by the court.
Also, when the trial was underway, main accused Raut escaped from the Sassoon Hospital here on September 17, 2011, while being escorted to the hospital for medical treatment. He was later re-arrested from Shirdi after 20 months.