Dropkick Murphys singer Ken Casey allegedly beat a concertgoer after he appeared to be making a Nazi salute over and over at a concert in New York last week.

Watch the highlighted video closely. On the left, a "fan," appears to act out a Nazi salute over and over again. Casey hits him with his bass guitar and chaos breaks out.

"As the band kicked into T.N.T. by AC/DC some moron started seig heiling  (the Nazi salute) in time to the beat.  Ken Casey noticed this and ran right over to the guy, smashed him in the  face, took off his bass and hit him with that and then jumped on him and all out  chaos ensued. We could only assume from our vantage point that said Nazi got his  (EXPLETIVE) kicked. About 30 seconds later Ken emerged from the pileup with his  shirt torn and made his way back to the front of the stage.” --rocksoff.com