Von Brunn - here in an undated file image - ran an anti-Semitic website
A US white supremacist accused of murdering a guard at Washington DC's Holocaust Memorial museum has died in a prison hospital, officials say.
They say James von Brunn, aged 89, died in Butner, North Carolina, where he had been awaiting trial.
Mr von Brunn had been charged with first-degree murder, killing in a federal building and bias-motivated crime over the 10 June attack.
He was shot in the face during the incident.
Mr von Brunn died shortly before 1300 local time (1800 GMT), Butner prison spokeswoman Denise Simmons was quoted as saying by the Associated Press.
Last September, Mr von Brunn, a Holocaust-denier who ran a racist, anti-Semitic website, asked for a "fair and speedy trial" when he appeared in court.
Mr von Brunn has long been tied to extremist groups and served a prison sentence for taking a sawn-off shotgun, revolver and knife into Washington's Federal Reserve in 1981, when the board was meeting.
In the June incident, Mr von Brunn shot 39-year-old security guard Stephen Tyrone Johns as he held the door open for him.
The museum was crowded with schoolchildren and tourists when Mr von Brunn entered the building.
Mr Johns - who had worked at the museum for six years - later died of his injuries at a hospital in Washington.