Raja Jackson, the son of former UFC light heavyweight champion Quinton "Rampage" Jackson, is in the crosshairs of the LAPD ... after brutally attacking an unconscious wrestling opponent.
The LAPD tells TMZ ... cops were called to the wrestling event Saturday night and took a police report ... and now the incident is being investigated.
As we reported ... video shows Raja pummeling his KO'd competitor, Syko Stu, at a private wrestling event at KnokX Pro Academy in Los Angeles.