Police in Sacramento, CA have interviewed a WWE fan who was punched in the face by CM Punk during a live televised event Monday night ... TMZ has learned.
The incident occurred on "Monday Night Raw" -- when Punk went into the crowd after a match ... and several fans began to get physical with him.
At first, Punk shrugged off the fans ... but the wrestler snapped when someone made contact with the back of Punk's head.
Punk unleashes a punch at the person he thinks hit him ... taking the guy down hard.
The victim met with police shortly after the incident ... and a rep for the Sacramento County Sheriff's Dept. tells us the man didn't appear to have any major injuries that required medical attention.
But later that night, the victim re-contacted police ... and said he had developed pain in his knees.
Cops say officers took the victim's statement and are determining whether to conduct a full investigation into the matter.
A rep for the WWE tells TMZ, "WWE security was unfortunately not in the appropriate place at the time. Given CM Punk's persona as a 'bad guy' fans were naturally heckling him, but unfortunately a few fans began shoving him and one struck him in the kidney and on the back."
The rep adds, "WWE regrets that proper security measures were not in place, and CM Punk apologizes for reacting in the heat of the moment."