An employee at Bloomberg News’ Beijing bureau has been detained on suspicion of endangering national security, according to the network. Bloomberg News reports that Haze Fan, a Chinese citizen, hasn’t been seen or heard from since she was marched out of her apartment building by plain-clothes security officials on Monday. After spending four days repeatedly asking for information about Fan, Bloomberg News was informed that she’s being held on suspicion of participating in activities endangering national security. A network spokesperson said: “We are very concerned for her, and have been actively speaking to Chinese authorities to better understand the situation. We are continuing to do everything we can to support her while we seek more information.” Chinese authorities reportedly insisted that Fan’s “legitimate rights have been fully ensured.”