There's a locked room at the top of Dorian's house. I didn't attach any importance to it at first. He could have locked up anything there that he wanted to keep safe from the servants even.
7 seconds sound clip from the The Picture of Dorian Gray movie soundboard.
You can hear this line at 01:40:42.435 in the Blu-ray version of the movie.
Quote context
[...]
- It's strange, his rushing away like that.
- He looked black as thunder. I thought perhaps he'd found out what I've been up to.
- What have you been up to, David?
- You'll put it down to jealousy. I don't deny jealousy's mixed up in it.
- What is it you've done, David?
- One night he heard a noise and went to investigate. It was 4:00 in the morning.
[...]