The FBI won’t give up on “finding out what happened” to former agent Robert Levinson, who the U.S. government believes died in the custody of the Iranians after vanishing more than a decade ago, according to an email FBI Director Chris Wray sent to the FBI workforce on Thursday.

Wray also writes in the email, which was obtained by The Associated Press, that he himself met with the Levinson family and “we explained that the most credible evidence we have collected over the past 13 years points to the likelihood that Bob died in captivity.”

“It pained me to deliver that news, but I believe that we owed Bob’s family a thorough and candid presentation of the information that we’ve collected,” Wray wrote.

Wray’s message did not elaborate on the “credible evidence” he said the family had received.

The email was sent a day after Levinson’s family revealed that U.S. government officials had recently told them that they believed Levinson was dead. U.S. officials have not specified the nature or circumstances of Levinson’s death, except to say they believe it happened some time ago.

The death is believed to have occurred before the outbreak of the coronavirus outbreak that has has gravely affected Iran, Levinson’s family said.

The email comes as Trump administration officials have called on Iran to provide a more complete accounting of Levinson’s abduction and his time in captivity. Secretary of State Mike Pompeo said in a separate statement Thursday that “only Iran knows for certain what happened” to Levinson.

Levinson disappeared March 9, 2007, when he was scheduled to meet a source on the Iranian island of Kish. For years, U.S. officials would say only that Levinson was working independently on a private investigation. But a 2013 Associated Press investigation revealed that Levinson had been sent on a mission by CIA analysts who had no authority to run such an operation.

In his email, Wray said the FBI would not give up trying to find out more information about Levinson’s captivity.

Though the FBI believes he is dead, “this does not mean that the FBI has given up on finding out what happened to Bob,” Wray wrote.

“We’re going to keep working doggedly to determine the circumstances surrounding Bob’s abduction and his time in captivity, to find the answers we all want and that the Levinsons deserve,” Wray said.

(AP)