Can you find if a person has been in prison?

Yes, either pay for a criminal background check, or look at the DOC sites of every state this person has been to (in which he has resided). The latter is free, and you can access state DOC's through Prison Legal News at: http://www.prisonlegalnews.org/(X(1)S(lkt3hayy3kdmmhrhvfm2g155))/InmateLocator.aspx?AspxAutoDetectCookieSupport=1(you'll have to copy and past it to the address line). If you get stuck, let me know.