The Honkai: Star Rail Hook quest is one of the many companion missions that lets you get to know some of the game's side characters. In this case, it's the leader of the mischievous band of underworld kids, The Moles. You might remember Hook from when you played hide-and-seek with her and her sidekicks when you first arrived in the region.
During your stay in the underground area, you should receive a message from another kid, Julian, asking you to head to the Great Mine to help Hook and her father out of some trouble. As the quest continues, you'll find yourself playing detective and aiding her in finding the thief who took her father's special prospecting device, but it can be tricky to know who to accuse. So, here's whodunnit in Hook's quest.
Which suspect to pick in Hook's quest
During Hook's first quest, you'll be helping her to recover her father's rare and valuable prospecting tool that was stolen from him during the chaos at the mines. After you fight off the miners attacking him and check he's okay at Natasha's Clinic, you'll have to head back to the mine to investigate things for yourself. After speaking to the four suspects hanging around at the miner's camp, you'll have to officially accuse one of them.
The options are: the cook, the tailor, the helper, and the merchant, but the correct answer is the cook. Head over to accuse him and continue the quest. The good news is that even if you accuse the wrong suspect and they make their escape, you can still continue and finish the quest, since you catch them while they're trying to offload the goods to Sampo and recover the device, albeit in a broken state.