I'm afraid the murderer will be revealed in the final episode almost as an aside -- "Oh, by the way, here's who really killed her." The ending of the original "Criminal Justice" was unsatisfying because of that, imo. I think
@100TonsofOrangeFury is right, there are too many possibilities left dangling to tie them all up in two more eposodes.
Both shows were (are) indictments of the justice system and the murder itself became (is becoming) secondary. As
@Air_Thurman linked author says, the crime is just an excuse the author uses to examine the cops, the jails, the lawyers and the impact on those who enter "the system," guilty or innocent.
@Been Jammin I read an interesting take on the cat. Someone suggested that the info the cat is "carrying" is on his implanted ID chip (the existence of which hasn't been mentioned in the show).
His idea is that the chip will show that the cat actually belongs to the murderer who was an on-again off-again live-in with Andrea in the brownstone. Ray, the investment guy at the funeral leaps to the top of his suspect list.
While I found the chip-in-the-cat to be a good answer to why the writer has kept the cat in the story, it seems the guy at the animal shelter would have automatically scanned for a chip even though Stone probably told him he "knew" who the cat belonged to.
The other hole in the theory, imo, is that if Ray had been close enough to have left his cat at the house, there would also be men's toiletries and clothing. But I loved the chip idea because it would be a reason for the cat's story line to be so prominent.
Considering what Ray told Stone about the step-dad's interest in wealthy old ladies, the SD takes a big jump up my suspect list. I've never liked him as a suspect, even after the scene at the funeral with Ray. I thought then that maybe Ray was the boyfriend Andrea was afraid of that night.
@3Gamma nailed Ray at the funeral as an employee of the family and I said the ownership/inheritance of the house could be a motive. Still looks that way.
Right now, though, Ray edges out the step-dad at the top of my suspect list. He didn't have a claim to the house, but if he felt he had a "claim" to Andrea, his passion might explain the 22 stabbings, I still don't see the SD or any other suspect we have met stabbing her that brutally. I'm gonna be pissed if the killer is someone yet to be introduced.
Am I the only one that thought (even for a second) that Chandra and Stone were going to end up in bed after he cut her off from any more drinks at the bar? When she pops up the next day all vivacious and spunky, I thought. "Holy crap. they DID!" Stone's no-big-deal attitude toward her was perfect confirmation, I thought.