Suppose John Doe is on trial for murder and Jane Smith is called as a witness. Suppose some question prompts Jane to take the fifth against self incrimination. My understanding is that the prosecution can offer blanket immunity to Jane.
What happens if the prosecution offers blanket immunity to Jane, and then Jane admits to the murder and describes how she framed John? Is she free from prosecution for the crime of murder? Or can she only be immunized against other crimes, not the crimes that John has been charged with?