Is this Legal? Can some type of justice be found?

My friend lives in thees apartment complexes (Not the safest area to live if you know what I mean). My friend's uncle had been staying in her room, she cleaned up her room grabbing papers he had left and just stuffed them into the trash with out looking at them. She put the trash in the dumpster and not too long did she see two men start to dig into the trash. One of the men was her uncle's friend. Her trash was the only trash in the dumpster. It is a community dumpster with no locks or signs that help prevent salvaging. They're also littering by throwing her trash on the ground. Is there anything she can do? Is there anyway that this is illegal?