Depending on what you use for an email service there may be little you can do in that respect. If you can see the full email header , that may give you some information so you can block the sender or their domain. This is just like spam email and very hard the true sender. In cases like this you need to track thing by IP and that is not an easy thing to do. Let us know what you are using for email and we be be able to help you stop the junk. The other thing to consider, if it looks like it’s coming from someone you know, have them run a virus scan to make sure they have not been affected and you should run one as well.