WASHINGTON (AP) – Newly released documents about a now-defunct business owned by Donald Trump reveal strategies for enticing people to enroll in real estate seminars even if they couldn’t afford it. That has opened the presumptive Republican nominee up to fresh criticism from Hillary Clinton that he took advantage of vulnerable Americans.

Clinton took to Twitter Wednesday to call Trump University “a fraudulent scheme.”

Clinton campaign aides plan to use Trump University as part of a broader effort to cast the Republican as a callous businessman who promises Americans ways to get ahead, but is only concerned with enriching himself.

Clinton has hammered Trump for appearing to cheer for the collapse of the housing market and for failing to make good on veterans’ donations until he was pressured to follow through.