Justin Bieber just took another step down the path to destruction -- he got into a scuffle with a neighbor that could lead to a serious battery charge.

The two men got into an argument on the boundary of their properties yesterday morning, and according to the unnamed neighbor, Justin got physical and threatened the man with harm. But Justin's peeps say the guy walked into Bieber territory and began screaming about loud parties that took place while he was on tour.

The Los Angeles County Sheriff's Department is trying to unravel the tangled mess.