Judge Pawan Kumar Tiwari said the sentence would be pronounced on July 24.
The case relates to the killing of Pinki Sarkar (20).
Pandher and Koli were held guilty of kidnapping, rape and murder in the case.
Most of the victims were young girls.
Prior to Pinki Sarkar case the two were convicted and sentenced in six cases, while nine are in various stages of trial, public prosecutor Jaiprakash Sharma said.
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