ROME, Italy — No one may ever know just why Brenda Leyland, a 63-year-old housewife from the idyllic English village of Burton Overy, Leicestershire, became obsessed with the case of Madeleine McCann, the little girl who disappeared from a holiday resort in Portugal in 2007, or why she believed McCann’s parents were involved. Last week, though, Leyland admitted to Martin Brunt of Sky News that she sent harassing messages to the parents of the missing child under the Twitter handle @sweepyface. “I’m entitled to do that,” she told Brunt as he warned her that she and scores of other so-called “Internet trolls” had been reported to police for harassment.

The video of her apparent admission went viral, and Leyland, who had been able to launch her messages against the McCanns from behind the shield of her anonymous handle, suddenly found herself tagged a “troll.” The press stalked her, publishing her name and several of her hateful tweets, including one in which @sweepyface wrote, “To Kate and Gerry, you will be hated by millions for the rest of your miserable, evil, conniving lives, have a nice day!”

On Thursday, Leyland fled her home after a photographer snapped her photo from behind her garden fence. On Saturday, Leyland was found dead, an apparent suicide in a hotel near her home. Now, in a slightly meta moment, Brunt and Sky News are being harassed by the online community who blame them for her death. In one tweet posted by a man who writes under the apt handle @incognito, Sky News is blamed directly. “Sky News no doubt contributed to the death #BrendaLeyland. Had it been police officers [who harassed Leyland] there would be an IPCC enquiry. Are Sky untouchable?” In several other tweets, the McCanns themselves are blamed for causing the death of the woman who allegedly harassed them.

Whether Leyland’s comments constitute true trolling or not, her death shines a spotlight on what is an international pastime for thousands of people who comment online about high profile cases like the disappearance of Madeleine McCann, the murder of Meredith Kercher and the murder trial of Olympic “bladerunner” Oscar Pistorius. Even Robin Williams’ daughter Zelda was cyberbullied to such an extent by what are known as RIP Trolls after her father’s suicide she chose to go offline for good. “I’m sorry. I should’ve risen above. Deleting this from my devices for a good long time, maybe forever. Time will tell. Goodbye,” she tweeted for the last time after someone posted a photo-shopped image intended to be of her father’s corpse.

According to a February 2014 study entitled Trolls Just Want To Have Fun conducted by Canadian doctors Erin E. Buckels, Paul. D. Trapnell and Delroy L. Paulhus, Internet trolls operate as “agents of chaos” on the Internet, exploiting hot-button issues for perverse pleasure. “Online trolling is the practice of behaving in a deceptive, destructive, or disruptive manner in a social setting on the Internet with no apparent instrumental purpose,” according to the report. “This is why novice Internet users are routinely admonished, ‘do not feed the trolls.’”

Victims of Internet trolls are often unsuspecting commenters who naively enter an online conversation, journalists covering big cases, or the main protagonists of the cases themselves. The McCanns have received online death threats, despite having been cleared by police of any wrongdoing in their daughter’s disappearance. The McCanns say they are desperately worried about the safety of their nine-year old twins who are often subjects of online abuse. Their complaints were given to police last month in what is being called a “secret troll dossier” that apparently lists the abusive messages and the Twitter users who sent them. Sky’s Brunt referred to it when he door-stepped Leyland.

The murder trial of Pistorius in South Africa generated hundreds of vile comments and tweets that ranged from comments about his prosthetic legs to sick jokes about his dead girlfriend. Nick Squires, the Rome correspondent for The Daily Telegraph says any time he has written about the murder of British Erasmus student Meredith Kercher and the conviction of American student Amanda Knox in Perugia, Italy, he is harassed by supporters of Knox’s innocence and also those who believe she is guilty. “I always felt I had covered the story objectively and that both sides were wrong,” he told The Daily Beast. “I see it as a badge of honor. As long as I got crazy abuse from both sides, I was happy.”

Tweets are the weapon of choice for most Internet trolls, but the Canadian doctors say that hurling insults on Facebook, Instagram and through news websites is also common. What separates the trolls from the exuberant or opinionated is anonymity. “The deceptive and ‘pointless’ disruptive aspects may distinguish trolling from other forms of online antisociality, such as cyber-bullying, where perpetrator identities are usually clear and the intent is more straightforward,” they say.

In cases such as a spate of recent suicides by adolescents who were bullied on Facebook, the perpetrators were well known. In the seedy world of Internet trolling, they are not because services like Twitter do not require users to register a verifiable real name, and because it is equally easy to set up an email account under a false name. Facebook recently deleted scores of accounts after instituting a rule that disallowed the use of fake names which could ultimately protect people from cyber abuse.

Many websites, including Twitter, have avenues to report abuse, but it is often difficult to stop trolls from just making up a new monicker to avoid a block and hurling more insults. A new website called Trolldor offers an analysis to identify trolling activity by measuring several variables in a Twitter user’s daily usage, including how many tweets are their own and how many followers they have. The makers say they developed the site to combat the defenselessness of Twitter users. “We feel that the behavior of some Twitter users is part of the problem,” they say.

After surveying more than 1,200 online community members who frequently comment and tweet, the study doctors came to the conclusion that internet trolls often exhibit traits known as the “Dark Tetrad” of personality disorders: narcissism, Machiavellianism, psychopathic and sadistic tendencies. “They share many characteristics of the classic “joker villain: a modern variant of the Trickster archetype from ancient folkore.”

But until and unless the developers of online media require verifiable registration and disallow the anonymity that acts as a shield, Internet trolling will continue to be a popular cyber pastime. “The Internet is an anonymous environment where it is easy to seek out and explore one’s niche, however idiosyncratic,” the Trolls Just Want To Have Fun authors conclude. “The troll persona appears to be a malicious case of a virtual avatar, reflecting both actual personality and one’s ideal self.” And when that “ideal self” is psychopathic, there is little that can be done to stop them.