Good team work, and @LosBastardos got it! Massacre is the song, here are the clues:
Clue 1:
A picture of 15 keys. "15 keys" is the name of a song by the legendary US alt. country band Uncle Tupelo. In the song "15 keys", Thin Lizzy gets a mention in the lyrics.
Clue 2:
Thematically, this...