Not much is known about Heather before her daughter, Ariel Peterson went missing. After afterwards, she dedicated her time to trying to find her daughter again. She is deeply haunted by and obsessed with her daughter Ariel's disappearance, which occurred five years before Sarah Bennett returns to Waterbury. It might just be because of her suspicion and paranoia, but Heather appears to have a sixth sense about Waterbury's residents and their dark secrets.
Heather cares about Ariel very much, and becomes obsessed with trying to find her - as any mother naturally would. This chase leads her down a never-ending spiral of depression and insanity that leads her to distrust and loathe the people of Waterbury.
Not much is known about Benny, but Heather clearly loved and trusted her husband, being one of the only people to believe he didn't rape and kill his daughter like the news falsely led people to believe. Between his death and her daughter's disappearance she was left alone to spiral into depression and seeming insanity.
While Sarah and Heather doesn't exactly know each other, Heather has placed her in the same category as all the other people of Waterbury - and treats her like garbage. Even storming into her old shop (Sarah's new art gallery) and rummages through Sarah's mail. It's obvious that she's not all put together, as evident from spitting on the glass as she walks away.
Justin Faysal & Robin Turner
During episode two, Heather threatens the two men and is suspected of planting a clue. Later when Justin turns out to have been poisoned, Heather becomes the prime suspect. Even though she was released later on, it's obvious that she doesn't have the best relationship with Justin and Robin.