It was reported on Tuesday that before he chose to vouch for the current archbishop Theodore McCarrick, the late Pope John Paul II was informed of the abusive ways of McCarrick, but chose to to promote him for archbishop of Washington regardless. He has publicly denied any knowledge of McCarrick's abuse. 

The abuse in reference was revolving around allegations of McCarrick's inappropriate sexual conduct with seminarians, who are usually younger students of the church, during his time as Bishop. McCarrick denied these allegations. Regardless, he was tried by the church in 2019 and was found guilty of sexual abusing minors. This lead McCarrick to step down from the College of Cardinals. 

It was concluded through a Vatican investigation that American bishops had reported "inaccurate and incomplete information," stated the investigation. 

Source: CNN 

https://www.cnn.com/2020/11/10/europe/cardinal-theodore-mccarrick-vatican-report-intl/index.html