- Video report by ITV News Presenter Mary Nightingale
A close friend of murder victim Molly McLaren has spoken of the dangers of cyberstalking.
Molly's killer used social media to track her down before he stabbed her to death in a frenzied attack at a car park in Kent last year.
Amy Lee, who was in contact with Molly in the minutes leading up to her death, told ITV News she wanted more people to be aware of the hidden dangers of social media.
"Cyberstalking is completely anonymous and it's hidden, you don't know it's happening, so when you do take that case to the police, they don't know at what point they're picking up your case," she said.
"And in Molly's situation it was very close to what eventually happened which is where he snapped.
"He'd been planning that for God knows how long, in complete secrecy, and nobody knew about it, whereas had he had been a physical person that people had seen, maybe we would have been more worried a lot sooner.
"People would have raised concerns quicker, and the police maybe would have acted faster or in a different manner, but nobody knew it was happening."
Experts say the issue needs urgent tackling.
Dr Emma Short, director of the National Centre for Cyberstalking Research (NCCR), said stalking had been profoundly changed by social media.
"We are now perpetually visible to people who we would not choose to be visible to," Dr Short said.
"So those people who might be fixated on us, or to wish us harm, can access a lot of information about us, even if we are very secure in our accounts and so on.
"We are likely to have associations with people who make postings, tag us into things, which keeps us within the view of that person who is in pursuit."
It comes as a new report from the Western University found 88% of people spy on their former ex's account with their own profile, and 70% admitted to using someone else's profile to look at an ex's.
The NCCR says 90% of cyberstalking goes under-reported, and 40 % is not prosecuted due to "evidential difficulties".
Ms Lee says you should make sure you're aware of what you're a posting on social media and who has access to it.
"Just look at your friends list, she told ITV News
"How many of those people do you really know? Do they need to be a friend on your platform? It's okay to get rid of some people that you're maybe not trusting of or you don't know, and that's okay."