MADISON, Wis. -

A federal appellate judge has ordered the unsealing of two sets of documents filed in a lawsuit challenging a secret investigation into possible coordination between Gov. Scott Walker's campaign and conservative groups.

The right-leaning Wisconsin Club for Growth filed the lawsuit in February, arguing the investigation violates the group's free speech rights. U.S. District Judge Rudolph Randa agreed with the group and has put the probe on hold.

Prosecutors have appealed Randa's stay to the 7th Circuit Court of Appeals, which unsealed 266 pages of previously redacted documents last month.

7th Circuit Judge Diane Wood on Tuesday denied a Club for Growth motion to seal attachments to one of its filings in the appeal and ordered they be released to the public. It's unclear what the attachments contain or when they'll be released.