After the whole "Nohman incident", and the cutscene where Ken explains your current situation in relation to Jehuty, you will find yourself back in the BAHship cargo area.
Moving through this area you will be contacted by a guy named Taper, who is hiding in one of the cargo crates. Rooms with crates are marked on your map.
As you go into a new area, Taper will give you hints as to his exact location. If you go from room to room without shooting a crate, eventually you will have enough information to make an educated guess as to which container he is hiding out in.
For example: Taper gave me clues that he was in cargo hold C, in a blue container, and the serial number contained a "6".
His location changes with every new game, so the container for me won't be the same for anyone else.
To make this even easier, save prior to shooting a container - that way if it is wrong you can simply reload the save. But also note that you have a total of 3 guesses here, so don't get concerned if you messed up, let's say, once.