Sirius Explains Crouch's Dark Past
Pages 523-529
Sirius tells Harry, Ron, and Hermione about Barty Crouch's rise in the Ministry and his brutal methods for fighting Lord Voldemort's followers, including sending his own son to Azkaban without a trial. Sirius also recounts Crouch's fall from grace when his son died in Azkaban, leading to Crouch's decline in influence.