"when you take someone's life you forfeit your own"

The picture which includes that phrase is one of a torn down and very slummy looking house. I believe one window is boarded up, while many others re broken or in a deteriorated state. The phrase "when you take someone's life you forfeit your own" is graffitied on the wall of the building between the first and second floors. In addition to this graffiti there is also a graffitied painting of someone in one corner of the house. This person is painted to a background of pure sky, and looks tranquil. The combination of the phrase and the portrait make me think that this entire house is in a way a memorial to the man depicted in the portrait. Now if this is a memorial to a murder victim, there could be a number of reasons why that phrase "when you take someone's life you forfeit your own" is touted. It could be a general anti-violence campaign that personifies the victim and is essentially an emotion plea to end violence. It could also be a memorial for the person, as well as a request for the courts to give the killer the death sentence, since that phrase could certainly be used to promote a pro death sentence agenda.