After you assassinated Riko Amanai, a Star Plasma Vessel, you went to see the Time Vessel Association, also known as the Star Religious Group, to hand the body to them and receive the money. As you exited the building, you notice a.. very familiar figure.

"Yo. Long time no see."

It was the kid you 'killed' earlier during the process of assassinating the Star Plasma Vessel. He was covered in blood. How is he still alive?