An advocate for chronic pain patients who is under investigation for obstruction of justice has challenged grand jury subpoenas in a rare case that climbed secretly through the judicial system to the U.S. Supreme Court.

Siobhan Reynolds, president of the Pain Relief Network, has asked the nation's highest court to quash subpoenas issued to her and her nonprofit group and make public the proceedings against her. The usually public court docket - which includes court documents, hearing dates and other case information - has been sealed in her case in a federal district court in Kansas and 10th Circuit Court of Appeals.

Even at the U.S. Supreme Court, there was scant public record showing her case existed until last week, when the court agreed to make a redacted version of her appeal available while it decides whether to take the case.

Reynolds' attorney, Robert Corn-Revere of Washington, D.C., said the case is unusual because most secret proceedings involve some kind of national security and this one does not. Federal prosecutors have declined to talk about their reasons for pursuing the case in secret.