The Washington Post reports that Jason Rezaian, the news agency’s representative in Tehran, has been arrested in Tehran along with his wife, Yeganeh Salehi, and two other U.S. citizens.

The report from July 24 indicates that reliable sources say the four were arrested on Tuesday July 22 and there is no clear report of the reasons for their arrest.

Rezaian, a 38-year-old Iranian-U.S. citizen, has been head of the Tehran office of the Washington Post since 2012. His wife, according to the report, has applied for U.S. residency and has collaborated with the National in UAE.

Iranian judiciary officials have said that the matter is under preliminary investigations and they will make announcements about it in the near future.