The RUC said Mr Collins had been killed by people using the methods of "primitive cavemen". The police would not be drawn into speculation on whether he had been killed by the IRA or by other republicans, though they said he had suffered such dreadful injuries that they had advised Mr Collins's wife not to view the body.
Heated political controversy meanwhile continued over the Rev Ian Paisley's action in the Commons on Wednesday when, under cover of parliamentary privilege, he named more than a dozen men who he said had been involved in the killing of Protestants in 1976.
The Democratic Unionist party leader claimed the men had been named in an RUC document as being involved in the so-called Kingsmills massacre in south Armagh. The RUC said yesterday it was attempting to check the authenticity of the document.
While Mr Paisley received support from some quarters he was criticised by SDLP deputy leader Seamus Mallon and by one of the men he named, who challenged him to repeat the allegations outside the Commons.
Mr Mallon said: "I am very angry about this. It puts people's lives at risk and takes away their good name." He said he personally knew many of the individuals involved "and it is inconceivable that they woud have been involved in the Kingsmills massacre or any form of paramilitary activity."
One of those named was a 51-year-old father of seven, Eugene Reavey, who lost three brothers in a loyalist attack on the day before the Kingsmills shootings. Saying he was horrified by Mr Paisley's accusations, he went on: "I'm an innocent man. I have never been involved in terrorism in my life. I have never even been questioned by the RUC. I find it all incredible."
His solicitor, Rory McShane, added: "We are going to ask for a meeting with the RUC Chief Constable to discuss the issue of Mr Reavey's personal security which is now in jeopardy. We want to ask the Chief Constable whether this document really does exist and, if so, how it was leaked."
The RUC, meanwhile, said that dissident loyalists may have been behind a pipe-bomb attack on the home of a Catholic family in Dungannon, Co Tyrone. A woman and four children were asleep in the house when the device was thrown in.
It did not explode and no one was injured. This was the latest in a series of sporadic incidents, spread over various areas of Northern Ireland, in which Catholic homes have been attacked.
Describing the killing of Mr Collins, RUC chief inspector Eddie Graham said: "He sustained quite serious head injuries with a number of stab wounds to his upper body. It's more akin to a crime carried out by primitive cavemen than it is of a country entering the 21st century."