The Metropolitan Police is investigating a catalogue of vile internet abuse targeting the family of Madeleine McCann including death threats.
Officers are in talks with the Crown Prosecution Service after being handed a dossier of more than 80 pages of Tweets, Facebook posts and messages on online forums aimed at Kate and Gerry McCann.
Over the past few years hundreds of shocking messages have been posted by 'trolls' who believe - despite no evidence - that the McCanns had some involvement in the disappearance of their daughter in Portugal in 2007.
These include suggestions that the McCanns should be tortured and killed and calls for them to "burn in hell".
Some messages are even directed at Madeleine's younger siblings, now aged nine.
Madeleine McCann disappeared in Portugal
Manipulated images involving the McCanns - many of them graphic - are also in wide circulation online.
One troll - who uses the Twitter identity "Sweepyface" and has posted dozens of anti-McCann messages using the #mccann hashtag - was confronted by Sky News.
When asked about her use of social media to attack the couple, she replied: "I'm entitled to."
The dossier - compiled by members of the public alarmed at the online treatment of the McCanns and shown to Sky News - calls on police and MPs to act to crack down on such abuse.
The Met wrote to the campaigners: "In consultation with the Crown Prosecution Service and the McCann family the material will now be assessed and decisions made as to what further action if any should be undertaken."
Among the messages identified in the dossier is an exchange on a message board which reads: "These 2 should burn in hell"; "I will supply the petrol"; "I'll supply the lighter - happily".
Other posts include: "We need some numbers for some assassins on taps", "I hope that the McCanns are living in total misery" and "I want to see them smashed up the back of a bus or trampled by horses".
In one of her tweets "Sweepyface" called for the McCanns to suffer "for the rest of their miserable lives".
In addition to threats and abuse, several trolls have claimed to live nearby to the McCanns in Leicestershire and reported on their movements.
The campaigner spearheading the appeal - who has asked to remain anonymous - told Sky News: "We're very worried that it's only going to take somebody to act out of some of these discussions, some of the threats that have been made, and we couldn't live with ourselves if that happened and we had done nothing."
Author Anthony Summers, whose book Looking for Madeleine was published last month, said: "There is a campaign of hatred against the parents.
"It is venomous and vitriolic, most of it done by cowards. We are taken aback by the extent of the sheer evil behind it all."