Fugitive whistle-blower Edward Snowden said in a magazine interview that he is sure his former employers at the National Security Agency are tracking his communications while in exile in Russia.

In a lengthy interview published Wednesday by Wired magazine, the 31-year-old former NSA contractor wanted on U.S. charges of theft and espionage also said he would gladly return home and face prison for his disclosures on massive private data collection if that would serve to end what he sees as the U.S. intelligence agencies’ surveillance abuses.

"I told the government I’d volunteer for prison, as long as it served the right purpose," Snowden told the Wired article’s writer, James Bamford, during a series of interviews at an undisclosed hotel in Moscow. "I care more about the country than what happens to me. But we can’t allow the law to become a political weapon or agree to scare people away from standing up for their rights, no matter how good the deal. I’m not going to be part of that."

During the interviews conducted in late spring, Snowden said he deliberately left a trail of "digital bread crumbs" so the NSA would know which secret documents and data files he had taken with him when he fled his contractor job in Hawaii 14 months ago.

He told Wired that the agency’s report that he took 1.7 million files with him suggested they had missed the clues he left so NSA officials could take whatever steps were necessary to protect sources and revise operational practices.

"I figured they would have a hard time," Snowden said of his evidence trail. "I didn’t figure they would be completely incapable."

Snowden told Bamford that the final straw for him was the NSA’s MonsterMind operation, a malware-detecting program that can retaliate against the source of infection without any human involvement in the decision. The source of cyber attacks can be disguised, he noted, opening the possibility of striking back at an innocent target and provoking confrontation.

Fellow intelligence agency employees had become inured to the wide-scale intrusions on private communication by the agency, Snowden said, a jaded indifference he didn’t want to acquire.

"It’s like the boiling frog," Snowden told the magazine. "You get exposed to a little bit of evil, a little bit of rule-breaking, a little bit of dishonesty, a little bit of deceptiveness, a little bit of disservice to the public interest, and you can brush it off, you can come to justify it. But if you do that, it creates a slippery slope that just increases over time, and by the time you’ve been in 15 years, 20 years, 25 years, you’ve seen it all and it doesn’t shock you."

Snowden said he left when he did and disclosed the surveillance excesses "before he too was boiled alive," Bamford wrote.