He couldn't find them.
3 seconds sound clip from the Star Trek II: The Wrath of Khan movie soundboard.
You can hear this line at 01:05:36 in the Blu-ray version of the movie.
Quote context
[...]
- It's all right. You're safe now.
- Made us say lies, do things. But we beat him. He thought he controlled us, but he did not.
- Captain. Where's Dr. Marcus?
- Where are the Genesis materials?
- Even the data banks were empty.
- Erased?
- He wanted to tear the place apart.
[...]