They must have thought somebody was in there. There wasn't though.
5 seconds sound clip from the Night of the Living Dead (1968) movie soundboard.
You can hear this line at 01:19:39 in the Blu-ray version of the movie.
Quote context
[...]
- Ah, things aren't going too bad. Men are taking it pretty good.
- You want to get on the other side of the road over there.
- Chief, do you think we'll be able to defeat these things?
- Well, we killed 19 of them today, right in this area.
- Those last three we caught trying to claw their way into an abandoned shed.
- They must have thought somebody was in there. There wasn't though.
- We heard 'em making all kind of noise. We came over and beat 'em off, blasted 'em down.
- Chief, as soon as you're finished, can I see you here?
- Chief, if I were surrounded by six or eight of these things, would I stand a chance with them?
[...]