Imagine there are OTHERS who wanted to kill him for his allowing films to be made of their sessions, or that there are OTHERS who wanted to kill him because he was not as "exclusive" as he was leading them to believe.
They come and escort him to the river ~ and one of them grabs his keys and wallet off his student desk!
They simply tossed him in the drink before they put his wallet and keys into his pocket, so they left them behind before they got caught with them.
The cops are no doubt evaluating all the evidence in that light.
Ok, from a murder’s perspective a bridge is a rather public place to commit a murder.
If you are going to toss an unwilling person off a bridge you might need some help and that means a witness/ accomplice.
If you drug the subject you will have to be a fairly large person to pull it off and you still need an accomplice for transportation because you have to leave the subjects car at the scene. If you walk you are going to be close to the scene of the crime too long.
If the video is the motive the police are going to come looking for you because they have video evidence that you knew the subject. Not too smart to kill him.
Murder is never a bright idea and is really stupid if you were intimate with the murdered.
Sure crimes of passion are not usually well thought out but tossing him off a bridge does not seem like a likely way to kill a lover. Bridges are more commonly ways to dispose of a body. Maybe a coroner’s report will come back with a murder finding.