Terrorists kidnapped four cocoa farmers at the Cocoa Research Institute of Nigeria in Ibadan on Wednesday.
The victims had arrived at the institute in the Idi-Ayunre area for a familiarisation visit.
They drove toward the nursing section when terrorists emerged from the bush and stopped their vehicle.
One farmer broke free during the ambush and reached safety.
He described the attack to authorities right away.
Oyo State police confirmed the details. The command rescued one victim and recovered the vehicle.
Officers now hold the rescued man in safe custody while they question him.
State Police Commissioner Femi Haruna directed the Anti-Kidnapping Unit and other teams to join local officers at Idi-Ayunre.
Operatives began a bush combing search across the area.
Police spokesperson Ayanlade Olayinka said teams continue work to free the remaining victims and catch the terrorists.
The incident adds to recent security concerns in Oyo State.
Farmers and visitors at the institute now face new risks in an area once known for quiet research work.
