A group of construction workers stumbled upon 46 ancient tombs, between 1,500 and 2,500 years old while digging to build a new soccer stadium in Deportivo Cali in southwestern Colombia, an archaeologist team said on Wednesday.

The tombs were found in Malagana, on the basin of the Cauca River. Anthropologist Jose Rodriguez, who headed a team from Colombia's National University, said that the tombs showed evidence of cannibalism and warrior activities.

On the building site, experts found human bones, primarily radius and ulna bones. Rodriguez said that this indicates ritual cannibalism. According to him the community members tried to acquire shamanic powers by eating human bone marrow or brain.

The anthropologists said that they also found the first female shaman in Colombia. She was identified because she was discovered buried face down, the position used even now in the Amazon by shamans, who believe that a face-up burial allows shamanic energies to escape the grave and harm the community.

The other items discovered included fine ceramic, carbon fragments, animal bones and seeds.