Gunman Kills Guard at U.S. Holocaust Museum in Washington

A gunman exchanged fire with security guards inside the U.S. Holocaust Memorial Museum on Wednesday. An injured guard -- Stephen Tyrone Johns -- died later in the afternoon.

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Fox News identified the suspect as James W. Von Brunn. He is reportedly an elderly man tied to a white supremacy group. Police would not confirm the identity of the shooter. Fox says the man runs a Web site that espouses extremist views against Jews.

The D.C. police chief described the gun as a rifle and it appeared that the shooter acted alone.

Law enforcement sources told WTTG/MyFoxDC.com that during a search of a car that is believed to belong von Brunn, investigators found a notebook with information about six to nine locations in the D.C. area, including the National Holocaust Museum. Other locations on the list included the U.S. Capitol, the White House, the Washington Post, and a FOX News location.

Investigators followed up at each of the locations, trying to find out if there were any sightings of the suspect or any correspondence, MyFoxDC.com reported.

Mayor Adrien Fenty says the suspect is hospitalized in critical condition.

The museum normally has a heavy security presence with guards positioned both inside and outside. All visitors are required to pass through metal detectors at the entrance, and bags are screened.

The museum, located just off the National Mall near the Washington Monument, is a popular tourist attraction. It draws about 1.7 million visitors each year. Several thousand people were in the museum when the shots rang out.

"Stephen Tyrone Johns died heroically in the line of duty today," museum officials said, in a statement. "There are no words to express our grief and shock over these events. He served on the Museum's security staff for six years. Our thoughts and prayers go out to Officer Johns' family. We have made the decision to close the Museum tomorrow in honor of Officer Johns, and our flags will be flown at half mast in his memory."

Mark Lippert of Lasalle, Ill., said he was at the museum when he heard several loud pops and saw several schoolchildren running toward him, three with horrified looks on their faces. He said when he saw the kid's faces, he knew someone had been shot.

Sandy Perkins of Massachusetts said her daughter, Abigail, called her shortly after the shooting. The teen was on a school trip to the museum and told her mother students heard several shots before they were told to leave the building.

Abigail said some of her friends from Holton Richmond Middle School in Danvers, Mass., were very shaken, but all were otherwise fine, Sandy Perkins said

The teens did not see where the shots were coming from. Linda Elston, who is visiting the museum from Nevada City, Calif., said she was on the lower level of the museum watching a film when she and others were told to evacuate.

"It was totally full of people," Elston said. "It took us a while to get out."

She said she didn't hear any shots and didn't immediately know why there was an evacuation. The experience left her feeling "a little anxious," she said.

Von Brunn is the authir of a book called "Kill the Best Gentiles."

The AP reports that in 1983 he was convicted of attempting to kidnap members of the Federal Reserve Board. He was arrested two years earlier outside the room where the board was meeting, carrying a revolver, knife and sawed-off shotgun. At the time, police said Von Brunn wanted to take the members hostage because of high interest rates and the nation's economic difficulties.