I am still mauling over the (physical) evidence...
The gloves: Profilers believed the gloves were staged. I agree. Criminals are often stupid, and might leave behind evidence. In this case, the gloves were in front of the bathroom door. The perp
could not have overlooked it while he (or she) was leaving the apartment. In fact, the placement of the gloves in front of the bathroom door would be so obvious, that I wonder if it was a staged staging...
Suppose that the glove has a good DNA sample from person X, and a weak DNA sample from person Y. Then person Z, the murderer, could have placed it there so that it would look like Y is the perpetrator trying to make it look like person X did it. Perhaps unlikely, but it might be a good plot for a crime novel
The crime scene: Although semen was found, there may not have been a sexual assault. The clothes were cutoff which suggests to me that they were removed when Julia was no longer conscious. This seem to have happened in the bathroom since some clothes were on the ground there. If there was a sexual assault it most likely would have been in the bedroom. But it seems that she had her clothes on until she got to the bathroom.
The semen: There are several possibilities. Jennifer said that Julia was seeing someone who had a vasectomy. That would explain the semen. The semen wouldn't implicate anyone in that case. Or the semen came from JT. It might not prove that he is the killer, but surely would make him a suspect because this would suggest at least an improper relationship. But the semen could also have been planted there by the perpetrator.