Can money or objects you buy with money be illegal

[zeppelinfan08]

Like if they're obtained illegally, by selling something illegal?

[Mr. Knowitall]

If you purchase assets with certain illegally obtained monies, or as part of a criminal venture (such as money laundering), the assets may be subject to forfeiture.

[zeppelinfan08]

What kind of things that would be sold could cause the money or assets to become illegal?