Dr. Alexander Tayler, who has been serving as acting CEO of Cambridge Analytica, has stepped down, the company's board of directors announced Wednesday. "[He] will resume his former position as Chief Data Officer in order to focus on the various technical investigations and inquiries," the company said in a statement. "We would like to thank Dr. Tayler for his service in what has been a challenging time for the company." The announcement did not name a replacement for Tayler. Cambridge Analytica became mired in scandal after it was revealed that the data-analytics company misused the personal data of millions of Facebook users. Facebook CEO Mark Zuckerberg, who is currently testifying before Congress, claimed Wednesday that his own personal Facebook data was accessed by the data-analytics firm.