Anyone following the news since Eurydice Dixon's death could be forgiven for thinking that grief has been the unanimous response.

The comedian's body was found on a Melbourne soccer pitch last week, and a 19-year-old man, Jaymes Todd, has been charged with her rape and murder.

Podcast The Signal The people trolling Eurydice's vigil The murder of Eurydice Dixon has shocked the country, and thousands have attended vigils. But the public grieving has also attracted trolls. Who are these people and can they change? About

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About 10,000 people attended a candlelit vigil at the Melbourne park where her body was found.

But this week, the vigil's organisers told The Signal they needed a team of moderators to mop up ugly responses on the Facebook event page, which had 20,000 responses.

"They clean up a lot of the stuff before I get to see it," said one of the event's organisers, Megan Bridger-Darling.

She said the team has had to delete comments quite frequently since the page was set up.

"Some are just absolutely terrible and vile," she said.

"[But] they don't hurt me as much as the women.

A team of moderators was put to work to clean up Facebook comments on the vigil's event page. ( AAP: Julian Smith )

"I saw one yesterday where was she was talking about 'if you left $100 on your dash, in your car, and you walked away, and someone stole that … that's why you need to wear a longer skirt'."

The backlash ranges from the "not all men" mantra, favoured by men who feel unfairly blamed, all the way through to pro-rape sentiments.

"They're sick of talking about gender equality, and sick of having to take lessons about how to be nice to ladies," she said.

"It's absolutely galling that you would equate this tragedy with that attitude."

Ms Bridger-Darling "without a doubt" interprets the defacement of Eurydice Dixon's memorial the night before the vigil as a real-world version of the same mentality.

Eurydice Dixon's memorial site was vandalised with graffiti. ( AAP: Ellen Smith )

"They did it in the middle of the night … and they desecrated a memorial to a victim," she said.

"When I think about the kind of person who would do this, I absolutely think it's a young man, maybe with his mates, trying to make a joke.

"Having to talk about this has absolutely destroyed my soul. Even having to acknowledge that this is happening."

Two kinds of trolls

The people whose comments are being deleted in this instance may fall into more than one category, according to psychology researcher Dr Evita March from Federation University.

She said one kind is trolls — or "cyber haters" as she prefers to call them, in order to avoid minimising their behaviour as a harmless prank.

"We're talking about people who … present as having high sadistic tendencies and also being high on trait psychopathy which means they actually lack a form of empathy," she said.

"What they get out of that behaviour is probably really difficult for us to understand because we would never do it."

But, she explained, that does not mean they were devoid of empathy — just one type of it.

Dr March said trolls were likely to be high in "cognitive empathy", which allows a person to accurately predict what another person will feel in a given situation.

It is distinct from "affective empathy" which might lead to compassion, rather than just a factual understanding of another person's emotional response.

On the other hand, she said, there are plenty of people who may seem like trolls, but are in fact expressing genuinely held beliefs.

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What they have in common is that both thrive in an online setting.

"You're de-individualised when it's not face to face," Dr March said.

"It makes sense, if we have a guise of anonymity we might be able to act out thing we wouldn't do face-to-face."

She said people are often emboldened by the abundant online opportunities to group themselves with like-minded people.

Many expressed their grief at the vigil in Melbourne. ( Triple J Hack: Jo Lauder )

"It's kind of like that idea of group hysteria — once something catches it gets amplified among members," she said.

Dr March believes some people with the psychological profile of a troll can be diverted from that behaviour if they receive empathy training at an early age.

"I'm hoping that these are things that are going to be implemented more often, particularly in schools."