On Tuesday, about a dozen people attacked Bridges after he stopped to remove a log blocking a road, police said. Bridges had been driving to a mining camp near Tsavo West National Park, near where he made one of his most precious discoveries of gemstones decades ago.
"We suspect those who killed him are probably employees of other people who want to mine in the area," said local Deputy Police Chief John Leshindoro.
Bridges was accompanied by his son, Bruce, in his 20s, and two colleagues during the attack. Police said his son was not hurt, but the two others were seriously injured.
A Kenyan lawmaker, Johnstone Muthama, said Bridges told police about three death threats he had received - and had named the people who had issued them.
The local police chief, Herbert Khaemba, told The Associated Press that Bridges had told police once about the threats. He said officers did warn those people to stop threatening the geologist.
Khaemba said he also asked Kenya's Commission of Mines and Geology to intervene, because those threatening Bridges were disputing his right to use a mining permit in the area. Bridges had been mining for gemstones in the vicinity of Tsavo since the early 1970s.
Muthama said Bridges' killing may have been motivated by anti-foreigner hysteria whipped up by political leaders.
"This is a problem caused by the leadership, who incite local people (by saying) that this is a foreigner who wants to take resources, so flush these people out," Muthama told The Associated Press.
Muthama, who owns a big gem mining business, said he had known Bridges for 25 years and together they founded the Kenya Chamber of Mines. Muthama is patron of that organization.
In 1968 Bridges discovered a rare green variety of garnet in neighboring Tanzania. Today the green gemstone, mined both in Tanzania and Kenya, is named tsavorite after the Tsavo nature reserve.
