and that the charges against her are out of time and consequently barred by the US statute of limitations.
Which Cases Do Not Have a Statute of Limitations?
There is no federal statute of limitations for certain crimes. A person can be charged at any time for the following:
Federal crimes punishable by death (U.S. Code 18 Section 3281)
Terrorism crimes that resulted in death or serious bodily injury (U.S. Code 18 Section 3286)
Sex crimes with a minor (U.S. Code 18 Section 3283)
Now, whether Mann Act or similar is actually a sex crime is an unknown to me.