On Pretty Little Liars Season 4, Episode 9: "Into the Deep," the "A" tag provided yet another clue as to who the main villain is when it showed "A" playing the piano while prepping some sheet music to send Toby's way. Of course, this immediately got us thinking about which characters we know definitely play the piano.

Here's the list of characters who are confirmed piano players that we've come up with.

Alison: As we saw in Season 4, Episode 10: "The Mirror Has Three Faces," Alison could play.

Spencer: We were also reminded of Spencer's music abilities in Season 4, Episode 10.

Melissa: We also know that Melissa has some piano skills; she used to play with Spencer.

Aria: Aria has also been shown playing the piano.

Of course, there are plenty of other potential piano players in the cast. While we're guessing we would already know if Emily or Hanna were musically inclined, highly suspicious characters like Wren or CeCe could easily have musical backgrounds. Still, add this as a point in favor of Melissa or Alison (or hey, even Aria or Spencer) being Red Coat.

Did we miss anyone? Sound off in the comments below!

Find more Pretty Little Liars spoilers here.

Catch the next episode of Pretty Little Liars on Tuesday, August 20, 2013 at 8 p.m. ET/PT on ABC Family.

Rebecca Martin is an editor at Wetpaint Entertainment. Follow her on Twitter @BeccaDMartin.