Longtime drummer AJ Pero of Twisted Sister and for the last few years Adrenaline Mob, passed away in his sleep this morning. Pero died of an apparent heart attack while on tour with Adrenaline Mob in Poughkeepsie, NY. He was 55. Vocalist Dee Snider tweeted out this statement: My friend, my brother, my band mate passed away today. My heart is broken. RIP A.J. Pero.