Music by Kevin MacLeod. Available under the Creative Commons Attribution 3.0 Unported license. Download link: https://incompetech.com/music/royalty-free/index.html?isrc=USUAN1100668

MacLeod's description:

Genre: Soundtrack
Length: 1:18
Instruments: Synths

1 of 8 in Ghostpocalypse. 100% atmospheric. No melodic or rhythmic elements.
ISRC: US-UAN-11-00668
Eerie, Unnerving 2010