There's also a possibility that it was a random act of violence by a stranger. However, as the fanfiction progresses, it could be revealed that there was some connection between this stranger and someone in Christy's life that was not known at first.
A business rival if Christy was involved in some kind of competitive field. They might have seen her as a threat to their success and resorted to shooting her to eliminate the competition.
It could be an ex - boyfriend who was jealous and wanted revenge. Maybe he couldn't handle the break - up and decided to harm her in this extreme way.
A possible suspect could be an informant who has turned on Tony. Maybe the informant was promised a better deal by another party if they got rid of Tony. Also, it could be a new criminal on the scene who sees Tony as a threat. This new criminal might be trying to establish their power and reputation, and taking out a well - known NCIS agent like Tony would be a big statement. Another suspect could be a person with a grudge against the NCIS in general, and Tony just happens to be an easy target.
Perhaps it's an insider within the law enforcement or criminal justice system who has a vendetta against the BAU. Maybe they disagreed with the way Derek and his team operate and decided to take matters into their own hands. It could be someone who feels that the BAU has too much power and is trying to send a message.
Well, it could be a rival of Ciel's in business or in a social setting. Maybe someone who is jealous of his status or wealth and sees shooting him as a way to get ahead.
A rival law enforcement agency member could be a suspect. Maybe they see Deeks as a threat to their own investigations or operations and decide to take him out. It could be a power play within the world of law enforcement.
It could be an old enemy from Beckett's past. Maybe someone they put in jail a long time ago, who has now been released and is seeking revenge.
It could be a random act of violence by a criminal who was in the wrong place at the wrong time. There are some bad elements in the area where Blaine was and they just targeted him without any specific reason other than opportunity.
Well, one possible plot development could be that after Christy gets shot, her friends or family rush to her side and try to find the person who did it. Maybe they start to investigate and discover some secrets in the process.
It could be an ex - lover. Maybe they had a bitter break - up and the ex - lover was filled with jealousy or revenge. Another suspect could be a business rival if Amy was involved in some sort of cut - throat business environment.
It could be a case of mistaken identity. Sam might look similar to someone else who is involved in some sort of illegal or dangerous activity. The real target's enemies could have thought Sam was him and shot him instead. In a fanfiction world, this could lead to all sorts of twists and turns as the characters try to figure out who the real target was and why they were being targeted.
Maybe in a fantasy fanfiction, an evil sorcerer is the villain. Christy might be a key figure in a prophecy to save the kingdom. So, the sorcerer tries to stop her by casting a spell that makes her get hurt. He doesn't want her to fulfill her destiny and will do whatever it takes to keep her from being a threat to his power.