The Justice Department recently sent grand jury subpoenas to Democratic Philadelphia District Attorney Larry Krasner’s office following a federal judge’s referral for a possible criminal investigation, a source familiar with the matter told the Washington Examiner on Tuesday.

The subpoenas concern possible obstruction of justice in the handling of cases before federal judges, the source said. They stemmed from U.S. District Judge Paul Diamond’s referral of Krasner and senior assistant Matthew Stiegler to federal prosecutors over their office’s handling of a challenge to a murder conviction.