As you know, Professor Bernstein had no living relatives.

4 seconds sound clip from the The Curse of Frankenstein movie soundboard.

You can hear this line at 00:38:47.108 in the Blu-ray version of the movie.

Quote context

[...]

- I really am most honored to have you here, sir.

- I'm most grateful to you, my boy. You know, I'm alone in the world. And to be guest in someone's home, especially such a charming home like this with such a wonderful atmosphere, it's very precious to me.

- You are too kind, sir.

- I'd like to show you a painting just before you retire. It's this one at the top of the staircase. It was purchased by my father and illustrates one of the early operations.

- If you step back a little, you'll see it better. Look out, Professor! Look out!

- Baron Frankenstein, I'm sure I'm expressing the feelings of all of us when I say how much we appreciate your kindness and consideration in allowing the body of our poor colleague to find its last resting place in your family vault.

- As you know, Professor Bernstein had no living relatives.

- It was the least I could do. He was a guest in my house.

- I thought I'd find you here.

- That was very intelligent of you.

- Now that you've found me, what do you want?

- You killed the old man, didn't you? You killed him and now you're mutilating his body.

[...]