The judge presiding over the case of a Chicago police officer charged with first-degree murder is seeking testimony from the journalist who was the first to write about the shooting of a black teenager.

Officer Jason Van Dyke’s attorney says Jamie Kalven obtained leaked documents about the shooting shortly after Laquan McDonald’s death in 2014. Attorney Daniel Herbert wants to know if the documents contain information from statements officers were required to give during the investigation of the shooting.

Cook County Circuit Judge Vincent Gaughan on Tuesday noted the law protects reporters from having to testify about sources except in certain circumstances. However, he added he was intrigued by Herbert’s characterization of the journalist’s involvement and the possibility the leaks may have come from a police oversight agency.

Kalven says he will appear in court when ordered but won’t reveal his sources.