Nikki Hallander was the older sister of Heather Hallander.
History[]
Nikki often bullied Heather by insulting her weight. She was the last person to see Heather before she disappeared, but it was later revealed that Nikki accidentally murdered Heather by pushing her into the chimney stack of their apartment after her sister caught her doing drugs.
When Kristen Vucelik masqueraded as Heather, Nikki became suspicious right away. After learning Kristen's true identity, she attempted to force Kristen to climb up to the chimney stack by showing her what happened to the "real Heather". The police were then able to prevent her from doing that. Nikki considered jumping off the roof out of guilt but her other sister Erica talked her down. She was taken into custody for her sister's death. (SVU: "Stranger")