ABC News has learned authorities are increasingly concerned that a man sought in connection with a bizarre shooting incident on the Washington Mall last week may pose a threat to President Obama. 
 
 The Secret Service now suspects that a bullet fired in this incident may have hit the White House after a bullet round was found in a White House window, though the round had not yet been conclusively linked to the incident. The round was stopped by ballistic glass behind the historic exterior glass, while an additional round has been found on the exterior of the White House. 
 
 Police believe the suspect, 21-year-old Oscar Ramiro Ortega of Idaho, is mentally ill. Ortega has an extensive record, ranging from domestic violence to drug charges. Sources say a police investigation has uncovered evidence suggesting Ortega has a fixation on the White House. 
 
 At 9:30 p.m. Friday, police received reports of shots fired in the bustling area of 16th street and Constitution Ave. 
 
 Authorities would later find a car in the area. The suspect had fled, but what police discovered inside the vehicle left them deeply concerned: an assault style rifle and empty shell casings. 
 
 Police linked the car to Ortega and have been hunting him ever since. 
 
 It’s unclear whether Ortega is capable of launching a sophisticated attack, but police are still fearful of what he might do next. 
 
 Authorities suspect Ortega has been in the area for weeks, coming back and forth to the Washington Mall. Before the shooting, he was detained by local police at an abandoned house. U.S. Park police say Ortega may have spent time blending in with Occupy D.C. protesters. 
 
 President Obama, who is currently on a visit to Australia, was not present at the White House at the time of the incident, and in fact has been out of town for the past week. Secret Service officials are not taking any chances with the security of the President and the White House, though, and want Ortega off the street. ||||| WASHINGTON (CNN) -- Police are still looking for a suspect in Friday night's shooting near the White House and Washington Monument and say they haven't found any bullets in buildings, cars or trees to indicate what the shooter might have been aiming at. No one was injured. 
 
 The U.S. Park Police have an arrest warrant out for Oscar Ramiro Ortega on a felony charge of carrying a dangerous weapon, and they would like Ortega to come forward. 
 
 "We want to hear from Mr. Ortega," said Park Police Sgt. David Schlosser." We want to hear his version as to what happened. This will help us fill in the blanks as to what actually occurred on Friday evening and we'd like to resolve this soon." 
 
 Witnesses -- including uniformed Secret Service officers -- heard shots fired Friday night. 
 
 Schlosser said he didn't know if Ortega had a history of anti-government activity or rhetoric and also did not know if he is a U.S. citizen. 
 
 Police found a crashed car near Theodore Roosevelt Bridge and say Ortega had been driving it. Schlosser said investigators found a semi-automatic weapon and shell casings inside the vehicle. That bridge is west of the White House and Washington Monument and is a major route into Virginia. 
 
 "The actions that Mr. Ortega participated on Friday evening -- that being the discharge of a firearm near the White House -- is an inherently dangerous activity, and because of that we do want to find Mr. Ortega as quickly as possible," said Schlosser. "At this point we're not certain what his intentions were." 
 
 On the same day the shooting incident happened, Ortega was stopped by police in Virginia around 11 a.m. for some sort of suspicious activity, said Lt. Joe Kantor with Arlington County Police. Kantor did not provide details on what behavior Ortega allegedly had been engaged in. 
 
 Ortega was not arrested in that stop, but Arlington County police took photos of him including one showing one of his tattoos spelling out the word "Israel" on his neck. U.S. Park Police later used those pictures in their releases asking the public for any information on the shooting incident. 
 
 Ortega is described as a Hispanic male, 5 feet 11 inches tall, weighing about 160 pounds. 
 
 According to the U.S. Park Police, the 21-year old Ortega has a history of criminal activity in three states that includes drug charges, underage possession of alcohol and assaults on law enforcement officers. Schlosser said the charges occurred in Idaho where Ortega was known to have lived, as well as in Texas and Utah. 
 
 Schlosser said law enforcement officials believe Ortega has been in the Washington area for several weeks. ||||| Investigators were examining evidence found in the car and talking with Mr. Ortega-Hernandez’s relatives, who told them that he appeared to have a fixation on the White House or President Obama , one official said. Another official said the Bureau of Alcohol, Tobacco, Firearms and Explosives had traced the origin of the weapon, but the official declined to disclose the circumstances of its purchase. 
 
 The United States Park Police had obtained an arrest warrant charging Mr. Ortega-Hernandez with a felony count of carrying a deadly weapon. The agency had also released photographs showing that Mr. Ortega-Hernandez had distinctive tattoos, including the word “Israel” on the left side of his neck. He was also said to have three dots tattooed on his right hand, the name “Ortega” on his back, rosary beads and hands clasped in prayer on his right chest and folded hands on his left chest. 
 
 The police in Arlington County took those photographs on Friday when they stopped Mr. Ortega-Hernandez after someone reported that a man outside was circling the area in a suspicious manner. Mr. Ortega-Hernandez was on foot and unarmed, said Lieutenant Joe Kantor, a county police spokesman, and since “there was no crime,” there was no reason to arrest him. 
 
 Late on Friday, the police searched the Occupy DC protest camp, on McPherson Square just blocks from the White House, after reports that the suspect might have spent time there. Protesters there said on Wednesday that the police had been through their encampment several times since then, showing around a photograph of Mr. Ortega-Hernandez. 
 
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 Sgt. David Schlosser of the Park Police said any motive would not be clear “until we can talk to this guy.” 
 
 He said Mr. Ortega-Hernandez had criminal records in Idaho, Texas and Utah for charges including drugs, underage drinking, domestic violence, resisting arrest and assault on a police officer. Public records indicated much the same thing. 
 
 The Secret Service did not have Mr. Ortega-Hernandez on record as someone who had made any threats to the president, an agency official said. 
 
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 Mr. Obama and his wife, Michelle, were away on Friday; the president was in San Diego on his way to an Asia -Pacific economic forum in Hawaii , and on Wednesday was in Australia . 
 
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 It was not clear for several days that someone had deliberately fired at the White House. But the Secret Service has now found at least two bullets. The agency would not say where the White House had been struck, but workers on Wednesday were examining a window overlooking the Truman Balcony, an area outside the second-floor residential quarters where the first family sometimes relaxes or hosts guests. 
 
 A second round was found outside, and officials were searching the South Lawn for any other rounds. The area around the White House was generally more crowded than usual with police cars on Wednesday. 
 
 The shooting came from roughly 750 yards south of the White House, just outside the outer security perimeter. The security perimeter extends to the south edge of the Ellipse, a grassy area where the National Christmas Tree is displayed. It is across Constitution Avenue from the more distant Washington Monument. 
 
 The street area, usually open to the public, is one of the most guarded parts of the city — or of the country, for that matter — with the United States Park Police patrolling on the National Mall and the District of Columbia police on the streets. In addition, the Secret Service, with a uniformed force of 1,400 officers, has agents on guard at fixed positions on the White House grounds and on patrol nearby in cars and on bicycles. Streets are routinely shut down for motorcades. The Secret Service said its security worked effectively on Friday evening, though it planned to “scrutinize how we can make it better,” an official said. 
 
 The Secret Service said it had been tipped off to Mr. Ortega-Hernandez’s whereabouts by a hotel employee who recognized a photograph of him and called the Pittsburgh field office. The field office alerted the Pennsylvania State Police, which dispatched troopers to the hotel. 
 
 Investigators established Mr. Ortega-Hernandez’s route by talking to people who knew him, an official at the Secret Service said, and circulated photos of him to several hotels in the area. The investigation involved all of the Secret Service’s 122 field offices in the United States, the official said. 
 
 The last known episode in which bullets struck the White House occurred in 1994, when one round fired from the area of the Ellipse penetrated a first-floor window and landed in the State Dining Room, and another was found in a Christmas tree near the South Portico. President Bill Clinton and his wife and daughter were sleeping upstairs. No one was hurt.
– A suspect believed to have fired shots at the White House last week is still at large and police believe he may be a threat to President Obama. A semi-automatic weapon was found in a crashed car belonging to Oscar Ramiro Ortega, a 21-year-old Idaho man, CNN reports. Ortega has a fixation with the White House and a criminal record that includes convictions for domestic violence, drug offenses, and assaulting police officers, sources tell ABC. A bullet was found in a White House window after Friday's incident. It had been stopped by ballistic glass behind the historic exterior glass. Authorities believe Ortega has been in the DC area for weeks, repeatedly visiting the Washington Mall, and possibly blending in with Occupy protesters.