The court acquitted 22 others in the case.
Additional District and Sessions Judge Mohd Nurullah Ghori pronounced the verdict sentencing 14 persons, including main accused V Bhaskar, to life imprisonment.
He convicted them for murder and other offences registered under the Indian Penal Code and the Scheduled Castes and Scheduled Tribes (Prevention of Atrocities) Act, Dichpally Circle Inspector V Tirupati said.
According to prosecution, on September 15, 2013, FRO R Gangaiah, (42) along with an 11-member forest team went to Nallavelli village of K K Thanda (hamlet) of Dharpally mandal on an a tip-off that villagers had occupied forest land and were cultivating it.
The police during the course of investigation arrested the accused and filed cases against 36 persons for their alleged involvement in the brutal killing and the attack on forest officials, the inspector told PTI.
The remaining 22 were acquitted, he said.