When Brooklyn finally caught up with Draco, he openly admitted to her that he once killed a mortal child by accident 40 years ago. Say a rebel found an archive about a child being murdered and a nineteen-year-old girl's death in a car accident, then checks the latter and finds out Draco was the last person to see the girl alive. To a rebel, the girl's death might be nothing, but it's the child's death was taken under consideration. The rebels could think that Draco was behind the death of Aurora's mother seven years ago, so they capture him to question him.
Is that enough of an explanation?
