U.S. offers $5 million for missing American, appeals to Iran

US: The United States increased the reward from $1 million to $5 million on Monday for helping to find an American who disappeared in Iran eight years ago and appealed to Tehran for help in locating Robert Levinson.

"We ask the Government of the Islamic Republic of Iran to work cooperatively with us on the investigation into Robert Levinson's disappearance so we can ensure his safe return," Secretary of State John Kerry said in a statement.

Levinson, a former FBI agent disappeared from Kish Island, Iran, on March 9, 2007, while on a business trip as a private investigator. Friends of Levinson said that, around that time, he had been investigating the counterfeiting of cigarettes, though mainly in Latin America.

The FBI has been investigating Levinson's disappearance. In 2012, it offered a rare $1 million reward for any information that could lead to his safe return. The FBI increased the award by $4 million on Monday.

"Year after year, the family has endured the pain of his absence. It is time for him to come home," Kerry wrote, also expressing concern for Levinson's health.

The latest plea for Iran's help comes as world powers are trying to reach a deal with Iran to curb that nation's nuclear program in exchange for easing some of the crippling sanctions that the global community has imposed on Tehran.

In November 2010, a video surfaced in which Levinson asked for help in winning his freedom but did not say who was holding him or where he was. The Iranian government has repeatedly said it knows nothing about Levinson's disappearance or whereabouts