At some point in her life, Cara married a man named Carl who she loved, but then "life happened" which led to the couple's end. She later stated that her ex-husband still kind of meant something to her but he did not seem to play a big role in her life anymore as she did not seem to bear any sign of lovesickness. Later Dean revealed that Carl died without a warning, allegedly "a heart-attack". He even suspected her to be the siren, unavailing though.
When she met Sam, with whom she got along immediately, she was having a hangover due to the previous night. They asked her about the autopsies she worked on plus the husband's blood. She told them there was nothing strange about the wives, but the husbands had an unusual amount of Oxytocin in their blood, which is only produced in the body during pregnancy, lactation and sex. As Sam left, he gave her advice about how to ease the hangover.
She bumped into Sam again when they returned for the blood samples, when Agent Nick Monroe appeared. The result was that they split up so Dean left with Nick and Sam stayed with Cara. Back in her office she discovered the blood samples were missing. Therefore, she stayed in her office with Sam to watch the surveillance camera's tape but since they could not discover anything and came to the conclusion that the tape must have been manipulated they stayed in her office talking. She took out a bottle of Whiskey, they drank and flirted and end up having sex in her office.