Nine bodies were found in three mass grave in northern Colombia, which police said could be linked to the conflict between two rival factions of Medellin criminal gang the Oficina de Envigado.
The remains, which were highly decomposed, were found close to the municipality of Sopetran, in Antioquia province, on Sunday.
The authorities said that the corpses likely include some of the 10 people abducted from a farm in the area on April 24.
The men were reportedly looking for allies of rival gang leader Erick Vargas Cardenas, alias "Sebastian," who were known as "Barney" and "El Gomelo."
Bonilla and Vargas are vying for control of the Medellin criminal world following the extradition of the Oficina's previous head, Diego Murillo, alias "Don Berna." Both groups are facing pressure from the authorities, with recent high-level arrests hitting the top of the organizations, as InSight has reported.