Members of a Canadian band sent a six-figure invoice to the US military after learning their music was allegedly used to torture prisoners at Guantánamo Bay, CTV news reports.

Skinny Puppy, an industrial rock band from Vancouver, wants $666,000 in royalties for the use of their music “as an actual weapon against somebody.” Keyboardist Cevin Key says the band learned its songs were played at Guantánamo from a former prison guard, who happens to be a fan.

“I am not only against the fact they’re using our music to inflict damage on somebody else but they are doing it without anybody’s permission,” said keyboardist Cevin Key in an interview with CTV.

Key added that Skinny Puppy is considering a lawsuit against the Department of Defense for using its music illegally.

US military commanders approved the use of music as an “enhanced interrogation technique” in 2003 at Guantánamo and secret prisons in Afghanistan and Iraq. An Associated Press report says interrogators blared music for days at a time “to create fear, disorient…and prolong capture shock.”

Former British prisoner Ruhal Ahmed, detained without trial at Guantánamo Bay for more than two years, says he suffered extensive music torture at the hands of the US military. Interrogators reportedly shackled his hands to his feet and his feet to the ground, forcing his body into a squat, while music blared for days. Describing that experience to Der Spiegel, he said:

You can’t concentrate on anything. Before that, when I was beaten, I could use my imagination to forget the pain. But the music makes you completely disoriented. It takes over your brain. You lose control and start to hallucinate. You’re pushed to a threshold, and you realize that insanity is lurking on the other side. And once you cross that line, there’s no going back. I saw that threshold several times.

Skinny Puppy joins a long list of artists who have objected to the use of their music for torture. Bands such as Rage Against the Machine and Nine Inch Nails, along with artists David Gray and Sesame Street composer Christopher Cerf, have all spoken out against music torture.

CORRECTION: Skinny Puppy reportedly sent a bill for $666,000 to the US military. An earlier version of this post said a different amount.