Harry didn’t manage to gather much more information about Riddle before the Triwizard Cup chose the champions. Everyone Harry asked about Riddle had good things to say; he was so smart, so handsome, so polite, so helpful. The only negative things anyone was willing to say involved Riddle’s arrogance (though this came from a pureblood witch who thought Riddle was too "uppity’ for a mudblood. Harry didn’t put much stock in her opinion) and his propensity for rigidly enforcing the rules (though this came from a Gryffindor girl irritated that Riddle had taken points from her when he’d found her wandering the halls after curfew, and as such was similarly useless).