CALLOUS killers Sean Swindon and Michael Peart subjected an innocent man to an horrific beating - then walked away as he was dying to celebrate with cans of lager.

The punched and kicked 36-year-old Keith Philpott over several hours, stopping regularly to make cups of tea and smoke cigarettes as their victim writhed in pain on the floor.

After tying him up with his own socks and beating him black and blue, they committed an act of such brutality that left even hardened detectives shocked and in disbelief.

Grabbing a knife from the kitchen, Swindon cut Keith Philpott's abdomen wide open and disembowelled him.

Mr Philpott, a kind yet vulnerable man with learning difficulties, was still alive when the first cut was made.

In fact, he was still fighting for his life as the pair casually cleaned up after themselves, picking up an ashtray full of cigarette butts and stealing the cups they had drunk from, taking away anything that could have linked them to the crime using DNA.

As their victim groaned in agony from his extensive injuries, Peart and Swindon, walked out of his home with several of his belongings including a phone, bike and distinctive ring, and locked the door behind them.

No attempt was made to contact the emergency services. Their intention was to leave their victim to bleed to death on his sitting room floor. Instead, the two killers spent the next day shopping - they were caught on CCTV buying cans of lager and trying to sell a ring that had belonged to their victim.

Detective Sergeant Andy Greenwood, of the murder investigation team, said: "It shows the pair of them walking around without a care in the world.

"They have shown no remorse at all."

Detective Superintendent Tony Hutchinson said: "You cannot imagine the terrifying state Keith must have been in.

"In his own home, he was tied up, beaten to a pulp and then tortured. He was tortured for hours.

"It is one of the worst assaults we have ever seen.

"They never panicked. To lock the door behind them as Keith was groaning is despicable.

"It was medieval what they did to him."

The pair had lain in wait for their victim to arrive back home at his Billingham flat and ambushed him on the doorstep.

Mr Philpott had spent the evening visiting friends and family proudly showing off a new pedal bike he had bought.

Despite his problems, Mr Philpott had wanted to lead an independent life. He kept his flat impeccably clean, but his mother still visited him each day to cook his meals and he kept in constant contact with his family.

It was his kind nature that ultimately led to his death.

A vulnerable soul, he was easy prey for the likes of Peart and Swindon, who had both been in trouble with the police before.

Surprisingly, it was Peart who had a history of violence, rather then Swindon, the main instigator of the murder, who had no convictions for violence on his record.

Mr Philpott had opened up his home to local teenagers, who would often visit to watch television and hang out.

From the age of 16, Swindon's sister, Gemma, had visited the flat and she and Mr Philpott had enjoyed a platonic relationship.

But, according to neighbours, Gemma took advantage of Mr Philpott's hospitality.

Sometime before the killing, Swindon was told Mr Philpott had molested Gemma and sent her sexually-suggestive texts but detectives found no evidence to support the claims.

It ultimately fuelled Swindon's anger towards his victim.

It was then he enlisted the help of Peart, who had never met Mr Philpott, and told him he wanted him to go to an address in Billingham to visit a man who he claimed was giving his sister trouble.

Mr Philpott, terrified after being confronted by Peart and Swindon at the entrance of his flat, barricaded himself into his bedroom, but one of the defendants kicked the door in, knocking it off its hinges.

The identical twin desperately tried to escape, but was dragged back into the lounge.

So appalling were his injuries that detectives believe it is likely he would have died even if his abdomen had not been cut open.

From the outset, police always believed more than one person had been involved in the murder because of the extent of the injuries.

Det Sgt Greenwood said: "We think they were egging each other on. The injuries were inflicted over three hours and to beat someone in that way would take at least two people."

Following media appeals for information, detectives were able to quickly identify their main suspects and piece together the events of that night.

Detectives became aware of Swindon because he had been reported missing from his girlfriend's home, in Middlesbrough, around the time of the murder.

The day after the killing, he was at Peart's home and he later went home to his girlfriend and confessed to the murder.

She persuaded him to go to the police and on March 26 he walked through the doors of Middlesbrough police station and confessed.

Because of the timetable of events, detectives began to look more closely at Peart and discovered he had also confessed murdering Mr Philpott to a friend.

A search of his home, where he lived with his parents in Norton, near Stockton, revealed clothing that linked him to the murder scene.

Swindon confirmed he had taken property from the house but strenuously denied anyone else was involved.

Det Supt Hutchinson said: "He always maintained he was on his own. We never believed it. To this day he has never incriminated Peart at all."

Though they may have believed they had got away with murder after cleaning up the flat, a lone cigarette butt was found that later revealed both defendants DNA.