"I don't think I'll sleep until they catch this guy," Lynn said.
Melissa's sister talked to Good Morning America with her face hidden for security reasons.
"I'm scared for my own protection, the fact that he's calling my phone. I have to be worried that it is going to happen to me one day," she said.
After posting a personal ad on Craigslist, Melissa disappeared in July of 2009.
Five months later, police found the 24 year old's skeleton, wrapped in burlap in the thick brush of Gilgo Beach.
"My fiancee and I looked at each other and started crying," Lynn said.
Up until that point, relatives believed Melissa was alive, maybe somewhere in a hospital near her home in the Bronx.
A few days after Melissa first disappeared, her baby sister, who was in Buffalo, got a phone call. For a split second, it seemed like it was from Melissa.
"It came up on her caller id - Melissa - and then when there's a guy on the other end," Lynn explained.
Over the next 5 weeks or so, he would call the then 15 year old five more times, eerily each time from Melissa's cell.
At one point the caller said he had killed Melissa.
"They were very taunting and angry words. My heart would stop and I just didn't know what to do," the sister said.
And now with the investigation widening, lynn is also at a loss. She keeps a close eye on her youngest, convinced whoever is doing this, could still be watching her.