As they get older, they don't always get more harmless. James Von Brunn, the 88-year-old white supremacist who was yesterday charged with the shooting that killed one security guard at Washington's Holocaust Museum on Wednesday, had attended fund-raising events for the British Nationalist Party among other activities.
He had also recently shown signs of going over the edge. He was "like a pressure cooker, just ready to go off", according to one neighbour. Nor did you have to be in his home town of Easton, Maryland, to notice. Mr Von Brunn had been dropping hints on the internet too, where he had learned to disseminate his doctrine of hate.
"It's time to kill the Jews," Mr Von Brunn, a hard-core Holocaust denier who once suggested that he had fought on the wrong side in the Second World War, declared in one posting. "America is a Third World racial garbage-dump – stupid, ignorant, dead-broke, and terminal," he offered in another.
You might think someone would have noticed Mr Von Brunn before he finally went off, killing the guard before being shot himself by two other security officers (he was in critical condition in hospital last night). In fact, the FBI and the Southern Poverty Centre, which monitors white supremacist groups, admitted they did know all about him. Sadly, however, there are many Von Brunns in America.
It was for this angry community that he wrote a book expounding his anti-Semitic views. Someone who got acquainted with him was Todd Blodgett, a former aide in Ronald Reagan's White House who had his own interest in the hate groups but also at times acted as an informant for the government.
Mr Blodgett recalled going with Mr Von Brunn to meetings in Virginia of the American Friends of the British National Party, a now disbanded group that raised funds for the BNP.
"Von Brunn is obsessed with Jewish people," Mr Blodgett told The Washington Post. "He had equal contempt for both Jews and blacks, but if he had to pick one group to wipe out, he'd always say it would be Jews."
If Mr Von Brunn had extreme views, he was also capable of extreme action. In 1981, he was arrested with a sawn-off shotgun outside a meeting of the Federal Reserve Board and imprisoned for six years for trying to kidnap the entire board, including the former chairman, Paul Volcker. At his trial, Mr Von Brunn said his goal was to "deport all Jews and blacks from the white nations".
The Poverty Centre confirmed that Mr Von Brunn had been continually monitored by its researchers since his arrest in 1981. While he had never heard Mr Von Brunn speak of taking violent action, Mr Blodgett said that "a lot of these people, when they get toward the end of life, they say they've wasted all these years hating, and they want to make a statement somehow".
John de Nugent, a self-described white supremacist who was in contact with Mr Von Brunn, said: "I think the election of Barack Obama became a tremendous signal of alarm for him."
DC gunman attended BNP rallies in US independent.co.uk/minority-report