This is a snippet from "Ride across the river", from Dire Straits. Notice the distorted guitar sound at the beginning; is that sound a result of two close notes (e.g. a semi-tone or tone apart) played together, just a distortion pedal or both?

Snippet (starting at 2min40s of the full soundtrack)

Original song (roughly at the same point)

P.S. I'm not quite asking for the exact notes, since I'll not try to play that particular song. I'm just interested in how to obtain this "growly" effect.