...you're going for second degree murder, becasue that's the best you can do under the circumstances, and then, before trial, e.g., a diary or "hit list" is discovered that names the victim, and details about the murder that will soon occur...This would then "upgrade" the charge to first degree murder, if the diary is linked to the alleged murderer...I'm giving an overly simplistic example, but you get the idea...Generally, though, everyone tries to "get on the same page" as fast as possible, and stays there unless something new is found, or something already found is investigated further...