By Adam Mynott
BBC News, Nairobi
There is enormous concern in athletics circles in Kenya that its pre-eminent position in long distance running is under threat.
It is not because other countries are catching up, but because Kenyan runners are deserting their country for riches abroad.
Lagat is the latest Kenyan athlete to defect and now runs for the US
The government has ordered an enquiry to find out how to stop Kenya's track stars from defecting.
In the Ngong Hills above the Kenyan capital, Nairobi, the views are breathtaking and the air is thin.
Molecules of oxygen are few and far between up here and the lungs of Kenyans born in this rarefied atmosphere are uniquely adapted to convert what oxygen there is into energy.
It is this "natural" advantage that has put Kenyan runners on top of the long distance runners' podium for decades.
Their brilliance has made them targets for an "international trade in runners".
Among the first to be lured away was Stephen Cherono, Kenyan gold medallist in the 3,000m steeplechase at the 2002 Commonwealth Games.
A year later he won gold at the World Championships as a citizen of Qatar, named Saif Saeed Shaheen.
He had defected for a monthly stipend of $1,000 a month for life.
Shortly afterwards Albert Chepkurui, the 5,000m runner joined him in Qatar, changing his name to Abdullah Ahmed Hassan.
"Athletics is a short career and I went there looking for a better life and better prospects," he said. "It's not that I don't like Kenya, I love it."
Chepkurui, or Hassan, spends several months of the year in Kenya.
His family live here and he still wants to train in the hills of Kenya, but Kenyan Sports Minister Ochillo Ayacko has had enough.
"The defectors and those who help them have interests which are hostile to Kenya," he said.
"They will now get very limited visas to visit Kenya and they will not be permitted to train in Kenya."
It all comes down to money. Kenyan runners who are successful can earn a good income by local standards, but it amounts to very little compared to what is available as a runner recruited by a Gulf state, for example.
Mr Komen said Kenya has "loads more brilliant runners"
It is now estimated that as many as 40 Kenyan athletes have defected. Bernard Lagat, the 1,500m runner, announced last month that he has become a US citizen.
He joins Wilson Kipeter (Denmark), Wilson Kirwa (Finland), James Kwalia (Qatar), Leonard Mucheru (Bahrain), Abel Cheuiyot (Bahrain) and so on.
One of Kenya's top coaches, Willy Komen, has a stable of runners he coaches in the Ngong Hills under the direction of world marathon record holder Paul Tergat.
When I met them, the runners were about to embark on a 30km outing.
"A bit of light training," Willy Komen described it, as the fantastically well-conditioned athletes disappeared over the horizon heading down into the Rift Valley.
Mr Komen said he was disappointed that stars were going abroad, but, waving at the cloud of dust the athletes had left behind, he said there were "loads more brilliant Kenyan runners who can take their place".
But the sports minister says the abuse by defectors of their former homeland cannot be tolerated.
There is evidence, he says, that some are now acting as "agents" recruiting runners for foreign countries. He has asked the committee to report back to him as soon as possible.