An FBI investigation was under way into the circumstances surrounding the death of the 34-year-old, who was killed by a single shot to the chest. The name of the dead man has yet to be released.
Last night the US immigration service insisted that the man had crossed the border illegally along a remote stretch of the frontier and attacked an officer who had challenged him. "The guy was walking down the highway with a large pack and one of the customs inspectors spotted him," said a Washington State border patrol spokesman "Suspicious that the man may have crossed the border without reporting, a border patrol officer was sent to check him out.
"When the officer arrived there was a struggle and the officer was assaulted. He ended up drawing his weapon and the man was hit."
The shooting occurred along the banks of the Kettle river, which runs from the mountains of British Columbia down to the Grand Coulee Dam. It is a sparsely populated area about 100 miles from Spokane, the nearest big town.
Bill Strassberger, a regional spokesman for the US Immigration and Naturalisation Service, said the man had been noticed jumping a fence near the Laurier border crossing, in north-east Washington State, shortly before 10.15am local time on Thursday.
He had travelled another five miles south of the border when an officer, sent to investigate, found him hitchhiking along a main road.
Mr Strassberger said the backpacker acted suspiciously when the agent questioned him, so the officer returned to his car to radio for back-up. "As he was going to his car the individual attacked him from behind, forced him down, started trying to grab for his gun. The agent fought back," Mr Strassberger said.
The hitchhiker then tried to strangle the agent with the microphone cord from his radio. The agent overpowered him and drew his weapon to hold him at bay, while ordering him to surrender. Undeterred, the man lunged again, Mr Strassberger said, so the agent fired "a single bullet". The shot hit the man in the chest, killing him almost immediately.
The British man had been deported from the US last month, but Mr Strassberger could not say why. Nor could he speculate as to why the man might have wanted to return to the country. Investigators making an initial survey of the scene said they found nothing suspicious in the man's pack.
Border shootings of this type are highly unusual. The FBI said it was looking closely into the shooting. The patrolman involved has been put on leave with full pay, as is customary in such cases.
The Foreign Office was trying to get details of the young man so that his family could be contacted. A spokesman said any investigation into the matter would be left to the American authorities. "It is not for us to look into it. It is for the authorities there to investigate. We will be trying to contact the family and offer assistance." He said the British consul in Seattle would be handling matters in the US.Reuse content