A crowd armed with clubs, spears and bows and arrows attacked and killed the geologist Campbell Bridges in August 2009, during a dispute over mining in a national park in the town of Voi, 110 miles north of the Kenyan port city of Mombasa.
Mr Bridges, a 71-year-old internationally renowned gemologist who had settled in Kenya in 1974, owned several gemstone mines in the Voi area.
He was attacked as he drove his pick-up truck with his son and four other Kenyans.
The accused – Mohamed Dadi Kokone, 42, Alfred Makoko Njuruka, 58, Samwel Machala, 49 and James Chacha, 56 – had denied the charges and were all out on bail except Kokone, who failed to raise a cash bond.
“The accused acted unlawfully. Even if the deceased was rightly a trespasser, they had no right to take matters into their own hands. This type of jungle law has no place anywhere in a civilised society,” Judge Maureen Odero said yesterday as she delivered her ruling.
CONNECT WITH THE SCOTSMAN
• Subscribe to our daily newsletter (requires registration) and get the latest news, sport and business headlines delivered to your inbox every morning
Ms Odero said witnesses had told the court that tension had been brewing between Mr Bridges and local small-scale miners who accused him of trespassing on their land.
Mr Bridges is credited with discovering the green tsavorite gemstone in the late 1960s in bushland on the border with Tanzania, according to the New York-based International Coloured Gemstone Association.
His obituary stated that when Mr Bridges was 29, an encounter with an angry buffalo near the Kenya-Tanzania border made his name among gemologists worldwide.
He dove into a shallow gully, where he lay until the animal lost interest. His face was pressed into the rocky ground and he found himself dazzled by green glints from the rocks, sparkling in the sun. “I had never seen a green like it,” he said. “It was pure in every sense.”
He staked a claim to mine it, took his first samples to Tiffany’s in Manhattan and found his rugged features being used in newspaper adverts, selling what was billed as “the tantalising jewel” – tsavorite. Tiffany’s kept him on as a consultant for the rest of his life.
It was after Tanzania nationalised its mines that Mr Bridges moved to Kenya, setting up a 1,500-acre series of ruby and tsavorite mines.
His son Bruce Bridges described his father’s killers as “bandits” – illegal claim-jumpers backed by a local Kenyan politician indignant over the success of a “mzungu” (white man) even though Mr Bridges had been in the country for years and treated his local workers well.
Bruce Bridges said the family had received regular death threats, but Kenyan police had done nothing.
“I saw the men who did this,” he said. “I know them: I know who funded it, who organised it and who carried it out.”
Mr Bridges was born in London but was proud of his Scottish roots. His mother, Barbara Carswell, was a Scot whose family, originally from Glasgow, had long held senior positions within the White Star shipping line, owners of the Titanic.
Mr Bridges is survived his by wife Judith, his son Bruce and his daughter Laura.
SCOTSMAN TABLET AND IPHONE APPS