If you've been watching The Jinx, HBO's documentary miniseries on Robert Durst, that eerie, ethereal music occasionally in the background is the musical saw, played by Natalia Paruz, NYC's "saw lady."
You can hear a bit of it in that clip, beginning around 0:09. My wife, the TV critic Emily Nussbaum, originally thought it was the theremin:
In The Jinx E2, is that theremin playing over the footage of Child Robert swimming w his mother? THIS IS THE KIND OF THING I NEED TO KNOW.
— emilynussbaum (@emilynussbaum) March 10, 2015
But Paruz tweeted back to say that, nope, that it was her — and that the director had specifically asked for that instrument:
@emilynussbaum No theremin on the score – the director specifically asked for a musical saw (represents Durst's demented childhood). (Cont)
— Saw Lady (@SawLady) March 10, 2015