A defense lawyer says two men have been sentenced to death over a fatal shooting that exposed class divisions in Pakistan and led to an unusual social media campaign demanding justice.

The wealthy pair, Shahrukh Jatoi and Nawab Siraj Talpur, stood accused of killing 20-year-old Shahzeb Khan in Karachi in December after Khan had an argument with one of Talpur's servants.

Khan's relatives said they had a hard time getting police to take the case.

Activists used protests, Facebook and other means to pressure authorities into action, and after the Supreme Court intervened, the suspects were arrested.

Hummol Zubedi, the lawyer for the accused, says Jatoi and Talpur will appeal Friday's court decision.

He says two others accused in the case were sentenced to life in prison.