There is no requirement that police stop a person who enters a police station and states that he wishes to confess a crime or a person who calls the police to offer a confession because volunteered statements of any kind are not barred by the 5th Amendment.
-- Earl Warren
   
Earl Warren   Name:
Earl Warren
Type:
Judge
Nationality:
American
Birth:
March 19, 1891
Death:
July 9, 1974
https://www.nutquote.com/quote/Earl_Warren