Robert Levinson

Robert Levinson vanished 2,456 days ago.

That makes the retired FBI agent the longest-held American hostage, according to the New York Daily News.

Journalist Terry Anderson was held hostage for 2,454 days. He was freed in 1991 by the Iran-backed Hezbollah in Lebanon, according to the Daily News.

Levinson worked at the FBI’s New York Field Office for 28 years.

He disappeared in March 2007 when was working as a private investigator in Iran, looking into cigarette smuggling.