What was the name of that sociologist who did a study on football hooligans& subculture and then became 1 too?

I think it describes the word 'going native' whereby the researcher begins displaying the same behaviour as his subjects. please please help me find it, i thought it was Paul Willis but its not. and can someone please clarify the words going 'going native'. i havent done this stuff since Alevels back in 2002 and i cant remember much as Psychology and Spanish was my first love. thank you so much and i look forward to your answers. ta-ra for now xxx