probably not without the help of law enforcement, unless the sender is sending from their 'regular' account, e.g. "jane.doe@hotmail.com". easy enough to find from what mail server it's coming, but identifying it past that will require the help of an admin for that server, and they aren't gonna tell you anything without a subpoena. if it happens to be coming from one of mine, I'd tell you, but other than that, sorry. could attempt to engage the sender in conversation in hopes of drawing out some identifiable info, but likely better to ignore them completely and wait for them to get tired of the lack of response and quit.