After the Hungarian killer described Keyzer Soze to the officers, a fax was sent to the police station of a drawn portrait that looked exactly like verbal that proved verbal was Keyzer Soze.
When Verbal walked out of the station, Kujan realized that Verbal was lying this whole time using details from the office that he was being questioned in.
Kobyashi, the guy that Verbal claimed was Keyser Söze's representative, was a name that Verbal came up with after he looked at the name of the brand of Kujan's mug, which was one of the things that made Kujan realize that Verbal was lying this whole time.
The group were lured into thinking there was cocaine in the ship. Soze was only using them as a distraction so he would be able to get into the ship and kill Astro, who was the only man who can positively identify him.
Verbal told the whole story based on real events; however, he fabricated most of the names and the way people were killed at the shoot-out on the ship.
The gang wanted to kill Kobayashi because Keaton didnt beleive in Kyzer Soze, and he thought that Kobayashi was the one pulling the strings.
Verbal was arrested and then released on bail, and while he was leaving, he took his belongings; a gold watch, a gold lighter and a pack of cigarettes (the gold watch that Soze was wearing in the beginning of the film).