man , 47 , faces 145 child exploitation offences after targeting kids online .
warwick man is accused of sexually abusing 28 children from three states .
victims could be as far as wa , as well as in victoria , qld and nsw .
he allegedly used social media to prey on children under the age of 16 .
in some cases he allegedly arranged meetings to physically abuse them .
he is also accused of forcing them to make child pornography .