Crime Scene -

The finger print analysis was interesting. The unidentified prints on her cigarette and on the laptop computer and the pregnancy tests tells us that the prints did not belong to Jeff, Kurt, Darren, Kyle, Elliot, Meg or Sophia. That means that they likely belong to Rita,Joanna,Eleana or Chris.
The fingerprints on the copier were to be as expected with the exception of one. Why were Elliot's prints on there? He shouldn't have had to copy anything. His job was to work on the computers.
Then there is the fact that Kurt's prints were on Annette's computer. He had no reason to use her computer. All the company computers are networked so they share the same company information. The only thing that would have been password protected would be her personal files. Was he trying to find out if she had protected files? They all should have had such files.
The prints on the envelope showed to only have Annette's and Meg's. Why would Meg have her prints on the envelope unless she was going through Annette's purse. Annette didn't like her so I can't see her handing money off to someone through Meg.
Points to ponder:
Darren did not get defensive when the detective asked if he got drunk because he killed her. His first interview enraged him at such a thought. His excuse of getting drunk because she didn't show up so he could ask her to marry him is pure crap. If you believe that I'll sell you the Brooklyn Bridge. His act is ridiculously bad. He is acting very guilty. He may or may not have killed her but he was suspicious of her. I think he was beginning to believe the stories of her being with other men and started following her and at some point that day, he confronted her about it.
Jeff pretended he did not know that the investigation was still ongoing even though no one had been arrested, which indicated to me that he thought he was in the clear. He said he thought the detectives said it was Chris Frost. No one said that and he knew it. It also doesn't take three weeks to run computer checks to find out what was going on. Jeff suspected it was Annette and he hire Elliot to make sure. Annette knew he was watching her so she strung Elliot along for a while, possibly with a little cash to go with her flirting, to stall things for a little while so she could get he plan in place.

MadisonCSI wrote:
That is something I looked up. I should have realized it sooner since I spent that particular night hunting nebula. New moons are the best time to do that. These investigations seem to run consistent with our real life environment, so I would consider it legitimate that Meg is lying about changing her mind about going to the office to moon bathe instead. There was no moon to "call to her" and she did go to the office. As you pointed out, she spoke of the murder as an accident. Her fingerprints are on the nail gun that she claimed at first, she never touched since it was first purchased years ago. Then her story about that changed, that she may have come into contact with it to put it away.

I'm going to go out on a limb here and suggest Meg wasn't the only one involved in the accident. Kurt Grubman's fingerprints are also on that nail gun. He also at first insinuated that he never had reason to touch that tool. I think they were monkeying around, maybe one of them was aiming it at Anette to pretend to shoot her and the other tried to take the nail gun away, and the nail gun went off and hit Anette. Now Kurt and Meg are covering it up.

The Grubman leaving the street so late at night was Kurt returning to the scene to retrieve something left behind. He had his headlights off so his wife wouldn't notice he left. That's why he didn't turn his headlights on until he reached the end of his street.

Kurt or Meg may have grabbed Annette's keys by accident and for some reason wasn't able to return them.

OR theory 2: Meg alone shot Anette and confided in Kurt in a late night call, and Kurt went there to help a very panicked Meg. They decided to tell no one. During that time Kurt touched the nail gun but decided to leave it lie instead of trying to dump it somewhere.