Nice mood and style! Reminded me of "Papers, Please".
The detective/interrogation work was interesting, though I wasn't sure what to do after I had grilled each of them once and talked about the new subject with the others. Didn't find any new dialogue to follow up on. I suspect Goldie did it, but couldn't prove it.
The text could go faster, and maybe even have the option of just having the text pop up at once. And I wish there was more to do during the interrogation, like pointing out discrepancies in their stories by asking certain questions in the right order (in one answer Shylock pretended not to know Digger's wife, but in other answers he clearly knew her well).
Not sure how the "holes" theme was present here, unless you mean the holes in the suspects' stories or the bullet holes in Mr. Digger's body. I do like detective games, though, so I'm happy you made one. The story, characters and the mechanics were interesting. Good work!