because it is impossible to disprove what it says.

(1) Like I said in my post above, this was not a "forensic study" in the sense of CSI. It did not have access to police reports or other investigative reports, and it investigated the scene of the crime a year later.

This report is a study on forensic psychology. It tried to build a profile of the victim and a profile of the offender to build the scene of the crime. The report had a decent amount of information on Seth Rich, but obviously had nothing to build their profile of the offender so it made assumptions (see page 11 of the report).

Honestly, most of these assumptions are just the things that are circulating around the Internet already and why the Seth Rich focus started. For example, the report includes the following logic: (1) There was no shell casing, (2) With no shell casing the scene must have been sanitized, (3) With sanitization the person must have been trained in elduing police, (4) Such an offender then must have targeted Seth as a hitman. (See page 13). This is unprovable, but it seems unlikely. Occam's razor would point to the more likely outcome that the shell casing was just never found (it isn't always). Once you eliminate assumption (2) above, (3) and (4) don't follow.

The report is basically just like this: it states facts about the crime scene, and then makes assumptions about those facts which are not disprovable and then concludes that there must have been more. This is a conspiracy theory.

(2) An Investigation Already Occurred and Further Investigation Could Happen

The DC police have investigated and found nothing. I have faith that the DC police did a thorough investigation based on common-sense determinations of why would they have a motivation to lie.

Just as importantly, if there really is something here, Trump can order an investigation. He is in charge of the FBI and the rest of the federal law enforcement branches. I have no problem with such an investigation, and it seems to fit with Trump's incentives to authorize it if there is anything there. But he has not done such an investigation, or if he has it has not uncovered anything.

(3) What is the motivation of Clinton?

See my post above. Even if it was a hired killer, why would Clinton be motivated to do it now that the Russia leaking theory is extremely unlikely?

In conclusion, it is impossible to disprove. Proving the absence of something is very hard. The totality of the circumstances just make this incredibly unlikely.