The Las Vegas Metro Police Department are investigating a fan who was caught on camera smacking Arizona Cardinals star QB Kyler Murray following the Cards win in Las Vegas on Sunday. 

Video shows Murray celebrating with Cardinals fans in the back of the end zone before he's smacked in the face by who police say is presumably a Raiders fan. Murray is seen reacting immediately to the smack but teammates jumped in the middle to deescalate things. 

Police also confirmed that a formal battery complaint was filed regarding “a spectator at the stadium [who] struck a professional football player.”

If it was a Raiders fan who smacked Murray, he had good reason considering how Las Vegas entered the fourth quarter with a 23-7 lead before Murray unleashed on them.