WASHINGTON -- A Colorado man who fired 20 to 30 shots at the White House with a semi-automatic weapon faced arraignment Monday on charges of willfully damaging federal property and possessing a firearm as a convicted felon, the Secret Service said. The possibility of additional charges, including attempted assassination, was left open.


Yellow police tape stretched across the White House lawn in the aftermath of Saturday's shooting spree, which represented the second major breach of security at the executive mansion in the past two months. President Bill Clinton was inside watching a football game on television at the time, but no one was injured, authorities said.


The gunman, Francisco Martin Duran, 26, of Colorado Springs, was tackled by two bystanders, witnesses said, and turned over to the Secret Service.


Secret Service spokesman Dave Adams said the firearms charge lodged against Duran carries a maximum penalty of 10 years in prison and a $5,000 fine.


Adams said Duran was jailed in the Army for 2 1/2 years after he was convicted in March 1991 on charges of aggravated assault with a vehicle, drunk and disorderly conduct, drunken driving and leaving the scene of an accident. He was later dishonorably discharged, which prohibits him from possessing a firearm. The property charge carries a maximum penalty of 10 years and a $10,000 fine.


Authorities searched Duran's home and car to try to determine his intent. A senior administration official said several handwritten documents were found in Duran's belongings, including an "ambiguously written" and rambling note. The note, outlining how Duran would want his affairs handled if he died, was "closer to a will than a suicide note," one adminstration official said. The note contained no threat against Clinton, he said.


Duran bought his Chinese-made weapon in Colorado Springs on Sept. 13, the same day the president signed into law the crime bill, which bans newly manufactured guns of that type, White House Chief of Staff Leon Panetta said Sunday.


Panetta said resolving the question of whether Duran was attempting to assassinate the president "depends on further investigation."


Richard Griffin, assistant Secret Service director for protective operations, said there was no indication that the gunman was working with anyone else. "I would not characterize this as an assassination attempt at all, no way," Griffin said. "The president was in no danger, whatsoever."


However, Special Agent Carl Meyer held out the possibility that additional charges could be filed.


"I would not eliminate assassination statutes," he said.


The president's wife, Hillary Rodham Clinton, was in California at the time and their 14-year-old daughter, Chelsea, was not home.


Panetta said at least eight shots struck the White House. Three hit the mansion portion where Clinton, upstairs, heard the "crack" of gunfire. Other shots hit the press room.


In Colorado, Duran's wife, Ingrid, told law officials that he left their home Sept. 30, saying he was going to pick up some items for target practice. He never returned and his wife filed a missing person report on Oct. 1, according to the El Paso County sheriff's office. Secret Service agents said Duran had a business address at the Broadmoor Hotel, a world-class resort, in Colorado Springs.