The defense wants reporter Jana Winter to identify the law enforcement officials who told her Holmes sent a notebook containing violent images to his psychiatrist before the 2012 attack.

His lawyers say whoever spoke to her violated a gag order and should be punished. They also say officers might have lied when they denied under oath being Winter’s sources, undermining their credibility as potential trial witnesses.

New York state’s top court ruled in December that Winter did not have to testify in Colorado because she is protected by her home state’s shield law, which says reporters do not have to identify confidential sources.

A Colorado court issued a subpoena for Winter’s testimony, but because she is based in New York, that state’s courts would have to enforce it.

Winter has said she would not identify the sources, even though the Colorado court could sentence her to jail for contempt of court for refusing.

Winter’s attorney, Dori Hanswirth, didn’t immediately return a call. Hanswirth previously expressed doubt that the Supreme Court would intervene.

The identity of Winter’s sources is not likely to influence the outcome of Holmes’ case. But the defense’s quest to identify them has dragged on for more than a year and drawn objections from Fox News and journalism organizations, who say it threatens reporters’ ability to do their job.

Any evidence about his mental state – such as the notebook – could be important in persuading the jury. Authorities have confirmed Holmes sent the notebook, but the contents haven’t been publicly confirmed.