He was the culprit. Experimenting with those devilish instant freeze solutions and for some criminal purpose, undoubtedly.

7 seconds sound clip from Batman (1966) - Instant Freeze (S1E7) TV Series.

You can hear this line at 00:06:16 in the Blu-ray version of the movie.

Quote context

[...]

- Yes. What is the point of his shenanigans?

- I see calling cards, Chief O'Hara. To let me know he's back in Gotham City.

- Of course, he wants revenge.

- I'm not so sure I blame him.

- It was an accident, Batman. You didn't mean to knock that beaker of instant freeze on him during a fight in his laboratory.

- The Boy Wonder is right.

- He was the culprit. Experimenting with those devilish instant freeze solutions and for some criminal purpose, undoubtedly.

- True, commissioner.

- Nevertheless I feel it's my duty not only to catch him but with all the medical know how at our command to help that sorry creature back to a normal way of life.

- Noble sentiments, Batman.

- Wasted on the fiendish likes of him.

- Perhaps, men. We'll soon see.

[...]