On the flight back to Rome, he insisted that Barros would remain bishop of Osorno, Chile, as long as there's no evidence implicating him in the cover-up.
"I can't condemn him because I don't have evidence," Francis said. "But I'm also convinced that he's innocent."
Karadima was removed from ministry and sentenced by the Vatican in 2011 to a lifetime of penance and prayer based on the testimony of his victims.
A Chilean judge also found the victims to be credible, saying that while she had to drop charges against Karadima because too much time had passed, proof of his crimes wasn't lacking.
The victims have said for years that Barros witnessed the abuse and did nothing to stop it. Barros denies the accusations.