tong shao , 20 , was an international student from china attending iowa state university .
her body was found in the trunk of her car in iowa city on september 26 .
police believe it had been for three weeks .
she died of blunt force trauma and asphyxiation .
her boyfriend , xiangnan li , 23 , was the last to see her , but flew to china on september 8 , before shao was officially missing .
according to tong 's father , an arrest warrant has now been issued .
however li has disappeared .