Classic case of misheard lyrics. Funny thing is, this whole song is built around that misheard part. It actually says 'merther' which is a word used to describe a trance you go into when you mix cannabis and reggae music.
I always felt like I was missing something when I listened to that part because it didn't sound right as 'murder' I mean, they call it murder everywhere, right? Anyway, yeah, that led me to researching it, and I found out why.
And as for my thoughts on this song itself? It's okay, but I think it could've been cleaned up more and had the volume balanced a bit more. Sorry, but I can't give this full stars. Maybe try again, and I'll see if I can't give that one a more favorable score.