Good morning!
A John Doe warrant is most typically used in bank robberies, where the face is known but the identity is not. The statute of limitations period is usually not relevant, and in bank and convinence store robberies the JD warrant goes up quickly.
The FBI states that only in "ironclad cases", where there is recent, solid evidence of an actual child molestation, will JD warrants be issued.
John Does #1 and #2 were captured after their faces were profiled on America's Most Wanted.
http://www.amw.com/site/thisweek/D/DoeJohn...johndoeCap.html
http://americasmostwanted.com/amw.html (you have to scroll to the bottom and click on #2's capture report)