to be a crime, it has to be perstent. it has to be constant harassment . >> in the age of twitter and facebook tom it is often hard to prove the identity of the by creating ever new profiles, stalkers can hide their identities much more easily nowadays, according to this former secret agent and stalking specialist. >> with the internet, a stalker can come into your living room, onto your desk, the laptop next to your bed. he could be in the cell phone in your pants pocket around the clock, and that's why stalking is a growing problem. >> in 2007, germany passed a law against stalking, but very few stalkers can really be stopped. victims' associations say more and more people are calling for help. >> us and as i decide i's no o you are stalking me. i should not try to persuade the stalker with arguments. most people fall into this trap, but that is just what the peetrar wants -- ur attention. >> she has managed to turn the bles. she publicized her stalker's name. she told all her relatives and acquaintances she was being d