Is it illegal to deliberately send flashing images to someone that you know has photosensitive epilepsy?

I have a friend who has photosensitive epilepsy, who is being harassed by a person that is going out of his way to expose her to things that may trigger a seizure.
Obviously, this is sickening… but is it possible that it is illegal? I wonder if there are specific laws about this, but could it fall into some type of law about an intent to cause harm? Beyond the harassment, itself?