for keeping evidence sealed..several cases at link...
https://www.rcfp.org/secret-justice-warrants-and-wiretaps/search-warrants
But, as stark as these differences seem, they often blend together in application during an active investigation. In the Times Mirror case, the court refused to recognize any right of access to warrant materials while an investigation is ongoing, allowing them to be sealed indefinitely. But even the Gunn court, which found that the First Amendment created a presumption of access to warrant materials, concluded that the government has demonstrated that restricting public access to these documents is necessitated by a compelling government interest the ongoing investigation.
It added that line-by-line redaction of the sealed documents was not practicable because virtually every page contains multiple references to wiretapped telephone conversations or to individuals other than the subjects of the search warrants or reveals the nature, scope and direction of the governments on-going investigation. And while the Goetz court remanded the case for a more detailed determination, the Fourth Circuit has found in subsequent cases that the interest in protecting that investigation may overcome any public right of access. (Media General Operations, Inc. v. Buchanan)