Brutal David Croke and Robert Knapp slew Mohammed Sabir Raja at his home, a jury decided yesterday after seven days of deliberations.
When Mr Raja opened his door to the two killers, one of the men raised a sawn-off shotgun and opened fire.
The shot missed and the cartridge lodged in Mr Raja's ceiling.
But the men were intent on murdering the Brighton landlord and, after a brief struggle, Mr Raja was stabbed five times in the chest and gut.
He called out to his teenage grandsons Rizvan and Waheed, who ran downstairs when they heard the shot. But they were too late to save his life.
Clutching his chest and crying out in pain, Mr Raja said: "These are Hoogstraten's men. They have hit me, they have hit me."
These were the last words he uttered before calling out for his long-dead mother.
Rizvan and Waheed Raja both gave evidence at the three-month trial of Knapp, Croke and Nicholas Hoogstraten, who denied murder.
Rizvan, now 21, said his grandfather's shirt was splattered with blood as he clutched his stomach or chest.
He said: "He seemed to be in a lot of pain. I could see there were tears on his face and his face was looking very disturbed."
Rizvan said his grandfather ushered him and his brother away.
Rizvan went into the kitchen where he was followed by the man with the shotgun.
He said: "He lifted up his gun and he aimed it towards me. I slammed the kitchen door. Then I was lying on the floor thinking a bullet would come through the door."
The next thing he heard was his grandfather screaming from the front room. He saw his grandfather holding a black kitchen knife and the gunman taking aim directly in front of him. Rizvan said he then heard a bang and saw the gunman run off.
Mr Raja was blasted through the eye. He would have died in a matter of seconds.
Only Croke and Knapp know who pulled the trigger but the evidence linking them to the scene was enough to convince a jury at the Old Bailey they were guilty of murder.
Rizvan said: "I ran back to where my grandfather was lying on the floor. I checked his pulse and his chest but I couldn't tell if his heart was beating.
"Then I got up and went towards the kitchen to get a towel."
Waheed had called for an ambulance. After the second shot he saw the men running towards their waiting getaway van.
Croke and Knapp ran to a white van with the word Thunderbird 2 on it. It was parked outside the Raja home in Mulgrave Road, Sutton, Surrey, facing towards Cheam.
The white Ford Transit, registration C702WBT, was hardly the most inconspicuous of vehicles. It was emblazoned with a series of green diagonal lines and its wheel inners were bright yellow.
Several witnesses reported seeing it in the area in the days prior to the incident. Others saw the duo making their escape.
Valerie Willcox identified Croke in a video line-up. She said: "It was two-and-a-half years after the event. I was surprised at my reaction to a particular face . . . I knew I could make an identification."
The two men drove to nearby Gainsborough Terrace where they set fire to the van with their tools inside.
Resident Margaret Perry watched from her bathroom window after hearing what sounded like an explosion.
She told the court: "There were smoke and flames coming out of the vehicle. They were throwing something into the van to set fire to it."
The van contained a variety of charred items, including gardening equipment and a knife with a blood stain that had a DNA profile matching that of Mr Raja.
There was also part of an unusual fertiliser bag, which matched one found in a garage belonging to Knapp's mother.
Meanwhile, emergency crews arrived at Mr Raja's home.
In a statement, ambulance technician Martyn Angiolini said he was first to inspect the body and saw Mr Raja's head in a pool of blood.
He said: "I took the towel off his face and as I did so I saw the man only had one eye.
"Where his left eye would have been there was a black crater."
Knapp and Croke were making their escape. They drove round the M25 heading east towards Kent.
At Crayford they stopped at a cash dispenser and Croke, of Bolney Road, Moulsecoomb, Brighton, withdrew £200.
The pair stopped off at the home of Doreen Tong in Crayford and the trio went to south-east London in search of drugs.
After buying heroin and cocaine they returned to Doreen's house and sat in the garden with her family. In court her father and brother testified to seeing fresh burns on the two men.
Back at the Raja house police officers and forensic scientists were examining the property. They took hundreds of blood samples of which only one did not belong to Mr Raja. It was Croke's.
Forensic scientist Martin Whittaker told the jury there was a billion-to-one chance that an inch-long smear of blood on the doorframe did not belong to Croke.
Croke, 60, told the jury he had been miles away painting his son's house in Enfield at the time. He also tried to wriggle out of the charge by claiming he had lent Knapp his cash card.
There was no forensic evidence linking Knapp to Mr Raja's home but records from his mobile phone showed he was in the area at the time of the crime and he was tracked driving eastwards along the M25 towards Kent in the hours after the murder.
Knapp, who used to live in Sussex but was latterly of Convent Street, Abbeyfeale, Co Limerick, did not take the stand.
Yesterday, the pair were found guilty of murder after almost seven days of deliberation by the jury. The six men and six women are still considering the verdict of Hoogstraten - the man who is alleged to have ordered the killing.
Hoogstraten, 57, of High Cross Estate, Framfield, near Heathfield, is accused of paying Croke and Knapp to kill Mr Raja after he accused the tycoon of fraud.
The judge, Mr Justice Newman, sent the jury home last night to return to court on Monday. If they are unable to deliver a unanimous verdict, the judge has given them the option of returning a majority.
The Crown claims Hoogstraten wanted Mr Raja dead because of a series of bitter legal wrangles between the two, culminating in Mr Raja accusing Hoogstraten of fraud.
The jury heard Hoogstraten referred to Mr Raja as a "maggot" but said the litigation between the two amounted to "peanuts".
Hoogstraten took the stand to say he had found Mr Raja a source of amusement but denied any part in the murder.
He said he had led a blameless life for more than 20 years, although he did admit to sending round "hefty builders" to evict tenants and setting dogs on a group of "hippies" who had to jump out the window to escape.
On the stand, Hoogstraten fought back tears as he spoke about his early days making money through stamp dealings and properties in the Caribbean.
The jury had heard Mr Raja's son, Amjad, describe Hoogstraten as a "loan shark".
But Hoogstraten told the court: "The minimum amount he was loaned was £100,000 and maximum was £700,000 to £800,000. Over a period of years it was a couple of million. That is not loan shark territory."
The jury was told of the complex legal exchanges between the two men. They had known each other for almost 20 years through property circles in Brighton and Hove.
Hoogstraten, who claims he is worth £500 million, was questioned about his diaries, which list a series of payments to Knapp in the months after the murder.
The millionaire said: "This would be the first time in history a contract killer has been paid in stage payments and in some cases by cheque."
He said a person making a contract killing would not know the victim and probably not the person taking out the contract.
He thought a hitman could not be hired for the £6,000 to £7,000 that changed hands between himself and Knapp and added: "The going rate for this sort of thing is £20,000 or £25,000.
"I'm getting this first hand from people in Belmarsh."
His case was summed up by Richard Ferguson QC, who said: "A contract killing you may think involves planning and expertise.
"This was a bungled farce, more like an attempted robbery than a killing. What happened on July 2, 1999, bears as much resemblance to a contract killing as Mr Hoogstraten does to Mother Teresa. They are miles apart."
He reminded the jury they should not judge Hoogstraten on whether he was a nice person.
Mr Ferguson said: "He is not on trial for being rich and powerful. He is not on trial for his attitude towards his tenants. He is not on trial for his use of Alsatian dogs or heavy builders.
"You are here to decide whether the evidence compels you to the conclusion Hoogstraten is guilty of murder."
Mr Ferguson claimed Hoogstraten had no viable motive for murder. His client was eccentric "at the very least" but was "careful, pedantic and meticulous" and questioned whether he would have hired two "clowns" to carry out the killing.
He said: "You may also think that with the wealth available to Hoogstraten, if he had wanted to arrange a contract killing, he would have hired the best."
The case continues.
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