It keeps getting worse for UnitedHealth Group Inc. investors, as a report of a criminal investigation into its Medicare practices sent the stock diving again in early Thursday trading.

UnitedHealth Group stock fell Thursday following a report that the Justice Department is investigating the company for possible criminal Medicare fraud. The news comes only days after the struggling health insurer announced the departure of its CEO Andrew Witty due to personal reasons and suspended its full-year guidance,

The U.S. Department of Justice is carrying out a criminal investigation into UnitedHealth Group for possible Medicare fraud, the Wall Street Journal reported on Wednesday.

UnitedHealth CEO Andrew Witty is stepping down for personal reasons and the nation’s largest health insurer suspended its full-year financial outlook due to higher-than-expected medical costs. Chairman Stephen Hemsley will become CEO,

UnitedHealthcare announced that CEO Andrew Witty is stepping down immediately from his role for “personal reasons”. He will be succeeded by board chairman Stephen Hemsley, who praised Witty’s leadership after CEO Brian Thompson’s murder last year.