The Role of Blood in the Death of Thomas Jennings

In 1910, there's not much more they could have done to test for blood. Thomas Jennings has an injury which is consistent with a bullet grazing him. The girl that was sexually assaulted can most certainly have led to bloodshed. And now does the father have lacerations or bleeding injuries from the combat? Or did the offender manipulate the body and possibly get some blood onto his coat?