If your brother is a criminal you should call the police and ask them what to do from there.
Narc, snitch or rat.
Aiding a criminal? Harboring a fugitive.
true
vilen
desperado
A Picture Framer
police
It's "Criminal" vs. "Civil" justice, that's why. Not criminal/victim :-)
You would call them a Forensic Scientist.
A picture on a wall could be a mural, a painting, a photograph. It depends on the picture.
A posed picture can be referred to as non-candid, or a portrait.