Help making npc for a one shot

Not sure about the flair

Im running a one shot where the party is playing the bodyguards of a foreign prince in a ball. A shadowy figure will attempt to kill the prince and fail, and the party will have to figure out who is trying to kill the prince.

The attempted assassin will be the chef who is secretly a cultist attempting to throw the kingdom into chaos.

What I need help with is coming up with other people in the castle to be red herring suspects.

Sorry if the grammar is bad English is my second language.