Hello, which source are you using? That may give some insight. Most servers will have the NPC list on the SQL and some others might have it somewhere thrown around in the source. If you wish to find a NPC your best bet is looking at it through the coordinates. Also creating a script like the following might help you find the NPC in order to remove/move it a lot faster:
Code:
if (Account.Role == GM)
{
Client.SendMessage("NPC ID: " + CurrentNPC, ChatType.System);
}
Every source is different, but looking at the NPC manager in the source file should give you an idea(if what you're running is C#)