WASHINGTON - An Idaho man charged with trying to assassinate President Obama by shooting at the White House practiced with his weapon for six months and may have been upset about the country's marijuana policy, prosecutors said in a newly filed court document.

Oscar Ramiro Ortega-Hernandez is awaiting trial for the 2011 shooting, which did not injure anyone but left more than five bullet marks on the Executive Mansion. Prosecutors filed a 14-page court document Tuesday that adds additional detail about Ortega-Hernandez, who allegedly shot at the White House the night of Nov. 11 while the president and first lady were away.

Ortega-Hernandez, 22, has pleaded not guilty to the attempted-assassination charge and other charges.

In the document, prosecutors said Ortega-Hernandez "expressed anger towards the government regarding the continued criminalization of marijuana," which they said he acknowledged smoking and claimed makes people more intelligent.

Prosecutors said they would offer evidence to show that Ortega-Hernandez's motive in shooting at the White House "was to punish and kill the president, who he believed was the head of a government that was oppressing its citizens in various ways, such as by continuing to criminalize the use of marijuana."

Ortega-Hernandez, who was arrested near Indiana, Pa., several days after the shooting, told investigators his car was stolen from him at gunpoint the same day as the shooting.