Answer:
"They heard!–they suspected!– they knew!– they were making a mockery of my horror!– this I thought, and this I think.
Explanation:
"The Tell-Tale Heart" is a short story written by Edgar Allen Poe. The story is about an unnamed narrator who has murdered an old man and is trying to hide his crime from the police.
The line from the text, that tells that the narrator is convinced that the police has heard his heartbeat is,
"They heard!–they suspected!– they knew!– they were making a mockery of my horror!– this I thought, and this I think."
In this line, the narrator is thinking that the police has suspected him and heard his heartbeat which is beating louder as he has comitted a crime.