"He had a score to settle with someone, and that person was angry. He knew it, but he had hoped he could fight him, even though they were meeting in a hostile place like Knockturn Alley. As you know, this place is not under the control of the Malfoys, and there are many unknown risks and fatal unexpected events that can occur. And indeed, it was fatal for him. His killer was very cunning - he made him go into Dawn Alley, where all the shops are closed and there are no witnesses."