The FBI is offering a $1 million reward for information leading directly to the safe return of one of its retired agents.

Robert Levinson disappeared five years ago this week on Kish Island, Iran. He worked at the FBI for 22 years before he retired, taking as a private detective. It was that job that sent him to Iran in March 2007, where he went missing.

U.S. government officials believe he may be a hostage, held by a group in Afghanistan or Pakistan. So they're launching a new reward campaign, and putting out leaflets, radio spots and billboard messages across Southwest Asia.

At a news conference in Washington, with a wall of current and former law enforcement agents standing behind him, FBI director Robert Mueller told Levinson's wife Christine that agents "share in your heartache."

"We are working every day to bring your husband, your father, your grandfather home to you," Mueller said.

Christine Levinson told reporters, "there are no words to describe the nightmare my family and I have been living every day."

Authorities released a video of a thin and haggard-looking Levinson in 2010. They say he has diabetes and hypertension, but likely little access to medical care.

Since then, James McJunkin, who leads the FBI field office in Washington, says there have been no public hints about his well being and no demands for a ransom.

Levinson will turn 64 years old on March 10th, McJunkin says.

"We're trying to underline the importance this case has to the FBI," he says. "We're hoping for a break here."

Update at 3:01 p.m. ET. Family Launches Twitter Feed:

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