CNN News:斯諾登未來撲朔迷離 或步前中情局叛逃者后塵

NSA leaker Edward Snowden better watch his back or some say he could suffer the same fate as former CIA defector Edward Lee Howard.

His usefulness might not last forever.

Filmmaker Robert Stone has written an open letter to Snowden in "The Wall Street Journal,"

comparing Snowden's case to Edward Lee Howard's, the only CIA employee to defect to the Soviet Union.

In this video posted on YouTube,

Howard's defection is described, as CNN has reported, Howard was trained as a spy to be stationed in Moscow and fully briefed on Russian spies.

But he was forced to resign after failing a lie detector test before ever being sent to the Soviet Union.

Howard moved to New Mexico in 1983 and, expert s say, plotted his revenge.

He contacted the Soviet consulate in Washington and said, you know, I'm a CIA officer.

I have secrets.

I know what we do in Moscow.

And I'm available.

Howard eventually made it to Russia in 1986 and gets asylum .

The FBI says Howard's info to the Russians resulted in the execution of a scientist.

When American producer Stone met Howard in 1993, he was living in a Russian home in the country side but wanted out.

In 2002, Russia said the defector died in a mysterious drunken fall.

He just died of falling down drunk downstairs.

It didn't seem credible to me.

Former CIA officer Robert Baer agrees that CIA and FBI remain skeptical to this day.

There is certainly suspicion inside the CIA and the FBI that Edward Lee Howard had his neck broken by the KGB.

He was an alcoholic.

He was causing a lot of problems for the KGB.

They had every reason to get rid of him.

And perhaps as Stone puts it, Howard, quote, "was likely a casualty of the Cold War finally warming over.

Ed's death resolved the problem to each country's satisfaction."

For now, Edward Snowden may look relaxed.

But waht lies in his future?

Former CIA analyst Robert Baer predicts a rocky road.

They're gonna keep him under full control.

He will not be able to leave the country without their permission.

And I don't think they'll ever trust him.

The Russians have never ever trusted a defector, ever.

As for Stone, who sees a possible parallel to Snowden's future, the advice is simple.

To Mr. Snowden, I'd say just, you know what, keep your entrepreneurial mind applied and don't cross your, the givers of your asylum.

For OUTFRONT, Susan Candiotti, CNN, New York.