Last year, Bill Whitaker reported on leaked records of the Catholic Diocese of Buffalo, New York. They showed Bishop Richard Malone concealed allegations against dozens of priests accused of abuse and allowed some to remain in ministry.
The whistleblower was Bishop Malone's own executive assistant Siobhan O'Connor.
"The reality of what I saw really left me with no other option because, at the end of my life, I`m not going to answer to Bishop Malone. I`m going to answer to God," O'Connor said.
On Wednesday, Pope Francis accepted Bishop Malone's resignation.
Watch the full report, "Inside the Secret Archive," below.