I posted this earlier, but I guess you missed it. Here, I'll post it for you, and others, again.
This falls easily under the heading of Criminal Harassment. Criminal harassment is defined as behavior that the harasser knows would cause undue fear, intimidation or persecution, and adversely affects the victim's safety and security. A victim may receive threatening or obscene phone calls, unwanted gifts, notes and text messages, or observe the harasser loitering outside home or work. Depending on the actions a perpetrator commits, criminal harassment can bring gross misdemeanor or felony charges.
This is usually handled at the state level, with laws varying from state-to-state. As I am unaware of which state this took place in, I cannot go into further depth.
Here is an example from Massachusets GeneralLaws/PartIV/TitleI/Chapter265/Section43A:
Section 43A. (a) Whoever willfully and maliciously engages in a knowing pattern of conduct or series of acts directed at a specific person, which seriously alarms that person and would cause a reasonable person to suffer substantial emotional distress, shall be guilty of the crime of criminal harassment and shall be punished by imprisonment in a house of correction for not more than 21/2 years or by a fine of not more than $1,000, or by both such fine and imprisonment. The conduct or acts described in this paragraph shall include, but not be limited to, conduct or acts conducted by mail or by use of a telephonic or telecommunication device or electronic communication device including, but not limited to, any device that transfers signs, signals, writing, images, sounds, data or intelligence of any nature transmitted in whole or in part by a wire, radio, electromagnetic, photo-electronic or photo-optical system, including, but not limited to, electronic mail, internet communications, instant messages or facsimile communications.
(b) Whoever, after having been convicted of the crime of criminal harassment, commits a second or subsequent such crime, or whoever commits the crime of criminal harassment having previously been convicted of a violation of section 43, shall be punished by imprisonment in a house of correction for not more than two and one-half years or by imprisonment in the state prison for not more than ten years.