Protecting the identity of a source
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
When a source is granted a promise that the source's identity will be kept confidential, the investigative agency and all other agencies that receive information obtained under the promise are required to take all reasonable precautions to protect the source's identity. Each agency will prepare for its investigators and agents implementing instructions consistent with this part.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.