She was standing on her balcony in a negligee.
4 seconds sound clip from the In a Lonely Place movie soundboard.
You can hear this line at 00:21:06.245 in the DVD version of the movie.
Quote context
[...]
- What time did you get home last night?
- Did you see Mr. Steele after he and the girl entered his apartment?
- Yes, about a half an hour later.
- I saw him at his door saying good night to her.
- How do you know it was a half hour later?
- Usually takes me that long to get ready for bed.
- Can you see Mr. Steele's door from your bedroom?
- She was standing on her balcony in a negligee.
- It was a warm night. My apartment was stuffy.
- You're sure he didn't leave with the girl?
- I believe he was looking at me.
- Considering that you've never met Mr. Steele, you paid quite a bit of attention to him.
[...]