Francis knows his history yet allows him to be in charge of the CDF. 

When Müller was bishop of Regensburg in 2004 he appointed a convicted pedophile, Rev. Peter Kramer, to be pastor of a parish. Müller knew he was violating the German bishops’ 2002 “binding” guidelines, which forbid active ministry for a priest who has been convicted of abusing a child. Müller concealed Kramer’s conviction from parishioners. Kramer sexually abused more children in his new assignment, was again convicted of child abuse. Müller denied any responsibility for the new abuses and even threatened legal action against his critics. 
Müller also said, "If Jesus forgave even the worst sinners, how could one deny the pastor a second chance?" 

I got no response from 2 letters sent to Rome, 1 to the US Nuncio and 1,to Listecki.

The Holy See is only responsible for Vatican City residents
Sending letters “would not respect the legitimate principle of diocesan autonomy and subsidiarity.” 
Victims do not matter.