Members of the public have handed a file stretching to more than 80 pages of Tweets, Facebook posts, and forum messages aimed at Kate and Gerry McCann to Scotland Yard, according to Sky News.
The material posted by online “trolls” is said to have included suggestions that the couple should be tortured or killed.
One message board comment reportedly said: “These 2 should burn in hell.” Sky News said other posts in the dossier included: “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”.
Some messages were said to have been directed at Madeleine’s younger siblings, now aged nine.
The posts were gathered by people who are concerned about the abuse.
One campaigner 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.”
The material is being assessed by officers who are liaising with prosecutors and the missing girl’s family.
A Scotland Yard spokes- man said: “We can confirm we received a letter and documentation on September 9 which was passed to officers from Operation Grange. They are assessing its contents and consulting with the CPS and the McCann family.”
Operation Grange is the name for the Metropolitan Police’s involvement in the search for Madeleine. She went missing in Portugal when aged three in May 2007.
Last year, Scotland Yard said around 1,500 additional crimes linked to internet abuse were being reported each year.