Poor Lucas

Exploration Stage: Foggy Backstreet
From: Rayden Stroke
Description: I don't understand how Carlos is connected with the events described in the messages. We need to find all the caches with these notes. The Shadow Lamp showed Carlos's memory: how he was taking a letter from a cache in a streetlamp. Help me find the right one!
Completed: Thank you for helping me find this streetlamp cache! There's a note inside: "Lucas is in danger, the Dark Hunter has divided us and is following him. I need help! Comet." Hmm, if I understand correctly, Carlos's son, Lucas, is in danger!