Iran may be holding a former FBI agent in a bid to exchange him for Iranians seized by U.S. troops in Iraq in 2007, a U.S. senator suggested Tuesday.

Robert Levinson disappeared from Iran’s Kish Island in March 2007. Iranian authorities have repeatedly said they don’t have any information on him, but that is widely doubted in the United States.

“On several diplomatic occasions when Bob Levinson’s name has been brought up to Iranian officials, the standard answer is, ‘We don’t know anything about that.’ But the next thing out of the Iranian officials’ mouths are to discuss the matter of the Iranians held by the Americans in Irbil, Iraq,” Sen. Bill Nelson, D-Florida, told reporters. “You can draw your own conclusions.”

U.S. troops arrested five Iranians accused of being members of an elite Iranian military unit during a January 2007 raid in the Kurdish city of Irbil. They were accused of supporting Shiite militias in Iraq, but Iran said they were diplomats and accused the United States of violating international law by raiding a consulate.

The United States said the men were taken at a liaison office that lacks diplomatic status. Two were released the next November.

Nelson and Florida Democratic Rep. Robert Wexler, whose district includes Levinson’s Coral Springs home, are trying to jump-start efforts to find the missing man. Wexler said Iranian authorities have not assisted the Levinsons, saying they have “zero knowledge” of his whereabouts and are stonewalling “any effort to gain pertinent information.”

Levinson’s wife, Christine, said her husband was working as a private investigator on a cigarette smuggling case when he disappeared.

Here’s the latest release from the FBI on the issue:

“The FBI’s investigation into Mr. Levinson’s disappearance is ongoing. We are encouraged by the Government of Iran’s offer to work with the FBI in an effort to locate Mr. Levinson and return him home to his family safely. We immediately responded to that offer accepting their assistance and continue to await a response. We are working closely with the U.S. Department of State to facilitate communication with the Government of Iran. We continue to update the Levinson family in this humanitarian effort. We ask anyone with information to come forward and contact the FBI at

Joseph Persichini, Assistant Director in Charge of the FBI’s Washington Field Office