While investigating Sicarius, Tara makes the difficult decision to ask to reopen an old case. The tricky part of this case is it made her partner Rebecca's (Nicole Pacent) career. Reopening and potentially changing the outcome could heavily impact Rebecca, especially since she has moved up the ranks in the Department of Justice.
It's revealed that Tara and Rebecca met through a support group, each working through the ending of difficult relationships. While they are happy and are even considering moving in together, what they've built is immediately fractured by Tara's request. She doesn't talk to Rebecca first, and though Rebecca asks her not to push it, Tara does. In the final episode, Tara wants to make amends, but Rebecca is offered a job in Sacramento and decides to take it.
Their downfall is an example of how personal relationships can sour due to working relationships. Their relationship is also an example of how not to communicate about and navigate difficult situations. Tara isn't upfront about her intentions regarding the case and tries to remedy the situation, only for Rebecca to shut down and make the decision to cut off contact.
With their relationship left the way it is, it's unlikely that we'll see the two back together when the next season starts. However, with the revelation of Gold Star, there is a significant chance that Rebecca will be back despite her new job.
