(CNN) Pope Francis is sending investigators back to Chile to look into historical child abuse and accusations a bishop covered up crimes against minors, the Vatican said Thursday.

Francis said the church should be ashamed of its treatment of victims, and must move past the historical culture of abuse and secrecy.

Archbishop Charles Scicluna, one of the Vatican's top prosecutors for sex abuse, and Monsignor Jordi Bertomeu will carry out investigations in Osorno over abuse by Chilean priest Father Fernando Karadima and his followers.

Karadima was found guilty of child sex abuse by the Vatican in 2011. Victims said Osorno Bishop Juan Barros, who Francis appointed in 2015 over local residents' objections, covered up Karadima's crimes

Francis had initially discounted the survivors' testimony against Barros, and defended him strenuously for three years, calling accusations against him "calumny."