Who is Captain Agurto Alvarez from Kon-Tiki: Across the Pacific by Raft and what is their importance?

Captain Agurto Alvarez is the man assigned by the American Embassy to drive Thor and Herman over the Andes Mountains and into the jungle to find fresh balsa logs. He carries many weapons to fight off bandits, but they encounter none during the trip. Agurto kills a poisonous snake that threatens to bite Herman.