Stalking, a crime of power and control, may take many different forms, including making repeated unsolicited phone calls, sending unwanted letters or other items, following or tracking their victim with GPS or showing up at their workplace or home. Cyberstalking is another aggressive behavior including unwanted e-mails, instant and direct messaging, or liking and commenting on social media posts. Stalking usually involves repeated visual or physical proximity, nonconsensual communication, and verbal, written or implied threats. Victims may experience anxiety, insomnia, social disfunction and depression.