June 7, 2013  -- In the wake of a pair of eye-opening reports on the government's domestic phone and internet monitoring programs, officials are turning their attention to who the source of the leaks was and how top secret information from one of America's most shadowy government agencies slipped into the open.

"It's completely reckless and illegal... It's more than just unauthorized. He's no hero," one senior law enforcement source told ABC News of the unidentified leaker. The source speculated that a single person could be behind both recent leaks to the British newspaper The Guardian and to The Washington Post.

Early Thursday The Guardian published a top secret Foreign Intelligence Surveillance Act (FISA) court document showing that the Obama administration, through the NSA, has been quietly vacuuming up tens of millions of phone records for Verizon customers in the U.S. Hours later, The Washington Post published what it said were presentation slides explaining the government's PRISM program, a 6-year-old program designed to pull in vast amounts of data -- from emails to chat records -- from the world's biggest web services. In its report, the Post said the source of some of their information was an intelligence officer.

"This guy's trying to be some kind of martyr," the law enforcement source said.

One source, who has appeared inside the FISA court several times, told ABC News it was extraordinary for the top secret Verizon order to be leaked and he's unaware of something like that ever happening before in the 35 years the court has existed. Beyond the physical security measures, the FISA court staff and Justice officials who work there hold the highest clearances and only a few of people at Verizon would have seen the order, the source said.

Another former law enforcement official said in a more general sense, the NSA has strict safeguards in place to prevent classified information from getting out, but the longer a secret program goes on, the more people have to be involved. It only takes one aggrieved employee or former employee to break their silence, the official said.

President Obama addressed the news reports today, saying "I don't welcome leaks."

"Our goal is to stop folks from doing us harm and if every step that we're taking to try and prevent a terrorist act is on the front page of the newspapers or on television then presumably the people who are trying to do us harm are going to be able to get around our preventive measures," Obama said. "That's why these things are classified."

READ MORE: 'Nobody Is Listening to Your Phone Calls, Obama Says

Julian Assange, the founder of the anti-secrecy website WikiLeaks, defended the leaker and compared him to Bradley Manning, the young American military intelligence officer who faces 22 charges that include aiding the enemy for leaking a trove of U.S. military and diplomatic documents to Assange's website.

POLITICS: Liberals, Libertarians Unite as Obama Faces Off With Obama

"Let's ask ourselves whether the whistle-blower who has revealed those, and there's more to come, is going, in three years time, to be in exactly the position that Bradley Manning is in," Assange told CBS's "This Morning."

If the leaker is in the government, former Deputy Director of the FBI Tim Muphy said he should be punished.

"You have an obligation when you have a clearance not to leak this kind of information," Murphy said.

The Direct of National Intelligence, James Clapper, said late Thursday, "The unauthorized disclosure of a top secret U.S. court document threatens potentially long-lasting and irreversible harm to our ability to identify and respond to the many threats facing our nation."

Concerning one such threat, three years ago U.S. officials said the government used email intercepts to track and eventually catch Najibullah Zazi, a Denver man who pleaded guilty to planning to bomb the New York City subway in 2009.

"If that intercept had never happened, Zazi [and his U.S. al Qaeda cell] would almost certainly have conducted three suicide attacks in New York City," said Seth Jones, terrorism expert and author of "Hunting in the Shadows: Pursuit of Al Qa'ida Since 9/11".

Clapper said the government is only authorized to sift through the mountain of phone and internet records it collects on Americans "when there is a reasonable suspicion, based on specific facts, that the particular basis for the query is associated with a foreign terrorist organization."

An FBI spokesperson said he expects an investigation is underway to identify the leaker or leakers.

CLICK HERE to return to The Investigative Unit homepage.