During an online discussion Monday, the man who leaked hundreds of pages of classified documents about the National Security Agency‘s surveillance program accused the U.S. government of “nakedly, aggressively criminal acts” and said he fled to Hong Kong because American authorities would prevent him from getting a fair trial.

Edward Snowden, who came forward June 9 to identify him as the source of the NSA leaks, also denounced President Obama for preventing investigations of “systemic violations of law,” and suggested the U.S. government might try “to cover this up by jailing or murdering me.”

Snowden said he had supported Obama because the president’s “campaign promises and election gave me faith that he would lead us toward fixing the problems he outlined in his quest for votes. … Unfortunately, shortly after assuming power, he closed the door on investigating systemic violations of law, deepened and expanded several abusive programs, and refused to spend the political capital to end the kind of human rights violations like we see in Guantanamo, where men still sit without charge.”

The 29-year-old, who was a computer specialist for the Central Intelligence Agency before landing a similar job with a contractor working for the NSA in Hawaii, said government officials “immediately and predictably destroyed any possibility of a fair trial” for him in the United States. Snowden criticized U.S. authorities as “openly declaring me guilty of treason” for what he called his “disclosure of secret, criminal, and even unconstitutional acts .”

Snowden said American have “been asked to sacrifice our most sacred rights for fear of falling victim to” terrorism, and said the government’s “draconian responses” against other leakers, including Army Pvt. Bradley Manning, have caused more leaks. “If the Obama administration responds with an even harsher hand against me, they can be assured that they’ll soon find themselves facing an equally harsh public response,” Snowden said.

The public response in the latest CNN poll shows that, while Obama’s popularity has slipped as a result of recent scandals, most Americans don’t approve of Snowden’s actions:

The poll indicates that for the first time in Obama’s presidency, half of the public says they don’t believe he is honest and trustworthy. And Americans are split on the controversial National Security Agency anti-terrorism program to record metadata on U.S. phone calls, but they support the NSA program that targets records of Internet usage by people in other countries. That doesn’t mean they necessarily like what is going on: Just over six in 10 believe that government is so large and powerful that it threatens the rights and freedoms of ordinary Americans.
A slight majority of those questioned in the poll, which was conducted Tuesday through Thursday of last week, disapprove of the actions of the man who leaked sensitive information about the NSA program. A similar number say Edward Snowden, who fled to Hong Kong, should be brought back to the United States and prosecuted.

In his online Q-and-A hosted by the British Guardian newspaper, Snowden said U.S. officials are lying about government surveillance programs. ”Seeing someone in the position of James Clapper — the Director of National Intelligence — baldly lying to the public without repercussion is the evidence of a subverted democracy,” Snowden said. “The consent of the governed is not consent if it is not informed.”

Snowden also criticized the media for being “far more interested in what I said when I was 17 or what my girlfriend looks like rather than, say, the largest program of suspicionless surveillance in human history.”

The federal government “is not going to be able to cover this up by jailing or murdering me,” Snowden said. “Truth is coming, and it cannot be stopped.”