"After Potter entered his fifth year, Dumbledore asked me to give him Occlumency lessons. From Potter's memories, I once saw glimpses of the Dark Lord." Snape slowly straightened his posture and continued.
"I suspect it was due to the abnormal connection created when the Dark Lord tried to kill Potter fourteen years ago. He is able to share your thoughts and see what you are doing. I believe the Dark Lord has also noticed this."
Voldemort's face instantly darkened as he stroked Nagini's body with displeasure. "Indeed. Ever since the incident with Weasley, I realized this and have used Occlumency ever since. How could a fellow like Potter possibly see into my mind?"
Chapter 474