kamron t. taylor was recently convicted of murdering nelson williams jr , 21 , in june 2013 .
victim 's father , nelson williams sr , 48 , says he is afraid taylor might ambush him .
he beat a guard unconscious , stole his keys and uniform , and fled in his suv .
taylor was awaiting sentencing at jerome combs detention center in kankakee , illinois , when he escaped early wednesday .
the 23-year-old fugitive is wanted for aggravated battery to a correctional officer as well as escape .
cash reward for any information has been increased to $ 7,500 .