Kate and Gerry McCann have been subjected to disgusting attacks by trolls, some of whom have suggested the couple be tortured of killed  

Targeted: Gerry and Kate McCann are still searching for missing Madeleine (inset)

Police are probing a dossier of vile tweets targeting the parents of Madeleine McCann.

Kate and Gerry McCann have been subjected to disgusting attacks by trolls, some of whom have suggested the couple be tortured of killed.

The dossier, which includes 80 tweets, Facebook posts and forum messages, was handed to the Metropolitan Police by members of the public who feared for the McCann's safety.

One message board comment reportedly said: "These 2 [the McCanns] 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, who did not wish to be named, 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 spokesman 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.

So-called trolling is a mounting problem for the authorities. Last year Scotland Yard said around 1,500 additional crimes linked to internet abuse were being reported to the force each year.