I know very little about Zhao and I do not know whether he owns a gun. Why are you asking? We can say for sure that Zhao did not kill DeWolf, because
he died earlier. Police beliefs that Zhao's death was an accident. I find that hard to believe.
According to the police, he took a break from work and went for a walk. From the place he works there is one obvious route for taking a walk, and indeed along this route is where his body was found. But in order for him
to fall to his death, he would have to lean far over the railing. But why
would he do that? There is nothing interesting to see from that point,
only some space between the building and the parking garage. This could possibly be a suicide, and perhaps "accident" is a euphemism. But if this was not an accident, nor a suicide, it must have been murder.
Zhao worked in the anatomy department, in the plastination lab. Basically,
what they do is process body parts of the deceased so that they can be used in medical education. I saw an exhibition of this once, at the Detroit Science Center. Interesting but a bit morbid.
Another coincidental fact, which is probably not of any importance is the following. The medical examiner's office is on 300 Ingalls street,
accross the road from 220 Ingalls street, where DeWolf was found dead.
In fact, the fraternity used to be at 300 Ingalls Street. Then they moved the whole fraternity building across the road on tracks to 220 Ingalls street.