What happened to the chauffeur in The Big Sleep? Let’s hear your best theories

So in The Big Sleep, a chauffeur's death is famously left mysterious and confusing for the readers.

A popular story says director of the movie version Howard Hawks asked Chandler who killed Taylor, and Chandler replied, "I don't know either."

The chauffeur was called Owen Taylor and he was infatuated with Carmen Sternwood.

So what is everyone's theory on this?

To refresh memories, here's a short of summary of what happened to him:

Motivated by jealousy and a desire to protect Carmen, who was being blackmailed over pornographic photos, Taylor shoots and kills the photographer Arthur Gwynn Geiger at Geiger's home.

After the shooting, Taylor flees with the camera’s film plates. He is intercepted by Joe Brody, a small-time crook who had been watching Geiger's house to get into the "blackmail racket" 

Brody hits Taylor on the head with a blunt object (saps him) and steals the photo negatives.

So enter detective Philip Marlowe into the narrative. Taylor's body is found in the surf, having driven off the Lido pier in a Sternwood Packard..

I'm interested to hear everyone else's theories on this. I can't make my mind up on whether it was suicide or murder by Brody's hand.

I think suicide can't be ruled out due to the fact Taylor would have been in a highly emotional adrenaline fuelled state after murdering Geiger and being sapped and robbed by Brody. He may have felt like he failed Carmen since Brody swiped her photo. This is the ultimate failure, as he's murdered a man over the photo/blackmail but the smutty photo has gotten into the hands of a crook, regardless. He may have seen suicide as the easy way out.

I also think Brody could also have accidentally killed him with the sap, and then staged the suicide. However, when reading it, I got the sense that Brody was more confused about Taylor's death than attempting to hide anything.

So what are your theories?