The pair attempted to beat Tintin in obtaining a rare diamond, the Heart of the Jungle. Perez, hailing from San Theodoros, was an engineer by trade and was the leader of the two. While engaged with Tintin in a melee combat for a diamond concealed in a fetish, Ramon and Alonso fell into the sea from the S.S. Washington and drowned. They are then both shown being dragged to Hell by demons using pitchforks to fork them in the back.
- In the animated series, Alonso survives along with Ramon and are arrested.