The son of a Scottish gemstone expert murdered by a mob in Kenya has told the BBC News website how he tried to fight off the attackers who ambushed them. Bruce Bridges, 30, witnessed the murder of his father Campbell Bridges, 71, by a gang armed with spears and machetes. "They were screaming, 'We're going to kill you all,'" he said. Mr Bridges also said he and his father had been receiving death threats for three years and accused the local police of "leaving them to die". Mr Bridges was born in Scotland, but had lived in Africa for most of his life. He was a world-renowned gemstone expert, credited with discovering the green Tsavorite gem, a rare stone unique to the region. He had also worked as a special consultant to the New York jewellers, Tiffany and Co. Ambushed Mr Bridges was attacked on 11 August by up to 30 men in the grounds of his 600-acre property near the southern Kenyan town of Voi. He was travelling in his pick-up truck with four guards and his son when they were ambushed. Bruce Bridges said the family had been threatened repeatedly in a dispute over access and control of their gemstone mines. "I was there when it happened. I was one of the people they tried to murder," he told the BBC News website. "This is something that has been going on for the last three years with illegal claim jumpers in the area - bandits basically. "It has escalated in the last few months and we have received multiple death threats, all of them documented by the police. "On that very day my father and I had heard these bandits were digging trenches on our land, so we took that information to the police and asked them for extra security. "They refused to aid us in any way and basically told us to go it alone. "They left us to die." Guards fled After leaving the police station, the group had to return to Mr Bridges' property because a group of tourists was waiting for them there. But on the way, they found the road blocked by thorn bushes and it was then they were attacked. "Suddenly, about eight men came charging at us waving sticks, spears, machetes, all sorts. They were shouting, 'We're going to kill you all,'" Mr Bridges said. "I looked to my left and my right and there were more of them streaming out of the bush. "Two of our guards then fled, so there were only four of us. "I saw one man with a spear lunge at my father. He used his hand to push the spear away, but then another man ran over with a knife and stabbed him. "I saw my father fall, and I could see the man with the spear standing over him about to stab him again so I rushed at him and hit him with my club. "He fled and I pursued him into the bush. I followed him for about 30 metres, but then I looked back and saw our two remaining guards being slashed and hacked with machetes. "They were greatly outnumbered so I felt that was where I should be, in that battle. "As I ran back a man came running at me with a machete. I managed to deflect his blow, but it grazed my neck and I got a 15cm superficial wound. "When I got back there, the gang began to flee. It was then that I looked down at my father. "He was in a very bad state. He was unconscious and bleeding profusely. I'm no doctor, but I knew it was very, very bad." Mr Bridges drove his father as fast as possible to the local hospital in Voi, but his injuries were too severe. "Once we got there the doctors looked at him and said there was no sign of life. I made them check four times, but he was gone." 'Amazing man' Mr Bridges has dual UK and US citizenship - his mother is American - and he is appealing to both countries to help catch his father's killers. "The family is destroyed - and we are angry. For this country to let what happened happen to him is a tragedy. "He was an amazing man. He was the world's most famous gemologist, and it's not just me saying that as his son - anyone in the industry would say it. No-one had a resume like him. "I am desperate to see some kind of independent investigation because otherwise I don't hold out much hope for justice. "And that's despite the fact that we know exactly who did it. Their first names, last names, they are the same people we have been complaining about for three years." Mr Bridges' body has since been flown to the capital Nairobi. The two guards who were attacked are being treated for serious injuries. Earlier, a close friend, the Rev John Ellison, 72, from Alton, Hampshire, told the BBC that he would have put up a strong fight. "He was very fit, strong and confrontational, but a lovely man nevertheless," he said. "He would stand up to anyone. He would have gone in with his fists flying if someone attacked him." Source: BBC