Now that you mentioned flash drive, this is just a pure speculative thought but one of the crime scene photos was a picture of T's linen closet. In it, there was a flash drive. Odd. People don't really keep flash drives in their linen closet right?
Could it have contained the letters that she was planning to plant in T's computer? I wonder if LE analyzed the drive. Is that why she begged and begged Flores to show the crime scene photos? She took the drive out of her pocket while taking shower after killing him, then left it inadvertently in the linen closet?
Watch from 2:53:00 to 2:53:40
https://www.youtube.com/watch?v=Cpcc37rmk4A
Okay, it's late, and I've had a little wine, but... What if she had planned shooting him in the shower - I'm a shot first diehard - and she was going to make it look like suicide. She had the letters on the flash and she was going to print them out. Even though it would be weird that he kept copies of the letters he had (not) written to her, it would give a reason as to why he had killed himself. Then when she made mess of killing him, she took the flash for later use.