A Serial Killer Terrorizes Long Island A call from a stranger, a negotiation over sex, and an agreed-upon price - $1,500 - that made it even easier than usual for a heroin user supporting herself through prostitution to cast aside caution and head out into the night alone. For 27-year-old Amber Lynn Costello, who had been selling herself since the age of 17, the offer was much higher than usual, yet in other respects not out of the ordinary. But on the evening of Sept. 2, 2010, Costello made that date and never came back. For safety reasons, she used the cell phone belonging to her roommate, Dave Schaller, to set up dates. On this particular evening, Schaller recalls, the man called three or four times. "She felt comfortable with him," he says. The last call came at 10:30, and moments later she headed out of the modest gray-shingled house she shared with Schaller in West Babylon, N.Y., wearing a pink hoodie and jeans. Schaller was well aware that Costello took risks, but within the parameters the two had set, he had learned to accept them. An "incall" was often preferable to an "outcall," and both were typically secured by means of paid ads Costello placed on backpage.com. She described herself as a Southern belle, and her picture showed a petite young woman with green eyes and brown hair. She would buy a new ad every few days, in order to keep herself at the top of the adult-services offerings. If it was an outcall to a hotel or a house, Schaller would often drive her and wait outside in his car. More often, clients would come to their house, and he would wait in the next room in case she needed him. Schaller recalls episodes where men threatened violence and he had to intervene, going as far as to chase several out of the house with a baseball bat. Amber was tiny - 4 feet 11 inches tall and weighing barely 100 pounds. "But she never thought anything would happen to her," he says. She thought she was indestructible. On the morning of Sept. 3, Schaller called Costello's sister, Kimberly Overstreet - Amber hadn't yet returned. He says she told him not to worry. And so he waited. When people living in such precarious circumstances suddenly disappear, they are not necessarily the highest, immediate priority for the authorities. Such was the case on Long Island, where, according to Suffolk County police, four online escorts were killed, at varying intervals, between 2007 and last September. Their bodies weren't discovered until December, and then only by accident, when a police officer and his dog were out on a training exercise. Within weeks, the remains of six more bodies - reportedly, one of them a baby - had been found. Thus began a sensational run of tabloid news, fueling speculation that the police had been caught off guard by what might be a dumping ground for a still-active serial killer. Standing on the side of Ocean Parkway, a four-lane road that runs along the southern part of Long Island, about 45 miles from New York City, one can imagine a grisly scenario: a killer parks, shoulders his load, and moves toward the dense, high brush. Forty feet in, he drops a dead woman in a burlap sack. In January, the women were identified as Maureen Brainard-Barnes, of Norwich, Conn.; Melissa Barthelemy, of Buffalo, N.Y.; Megan Waterman, of Scarborough, Maine - and Amber Lynn Costello. All of them had been in their 20s, and all had been strangled to death. Shortly after, it was reported that all four had been working as online escorts. Suffolk County Police search an area of beach on April 5, 2011 in Babylon, NY. For cops, such cases can be the toughest to solve. These were victims who lived in the shadows, using false names (Costello advertised herself as "Carolina"), engaging in reckless and illicit behaviors. They are survived by witnesses who themselves often live on the margins of society. Costello was never reported missing by her family. Kimberly Overstreet, her older sister, had tried to tell herself that Amber would reappear. "You always hold out hope," she tells NEWSWEEK. My heart sank when I heard that four bodies had been found. Schaller says he often had warned Amber that the life she was leading was extremely dangerous. "It makes me upset" to think of how she died, he says. As much as I did, it wasn't enough. Look what happened. Some of the families were disheartened that police didn't take them seriously when they filed a missing-person report. A sister of Maureen Brainard-Barnes alerted police right after she vanished in 2007, but says she was told, "Your sister ran away and doesn't care about anyone." Amber Lynn Costello had been in New York for only six months when she died, a week before her 28th birthday. She had lived most recently in Florida, working on and off as a waitress between stints as an online escort. She had married for a second time and had been living in Clearwater, trying to get off drugs and get her life in order. The sisters, who grew up in North Carolina, were close. Overstreet says that Amber was sexually molested by a neighbor when she was 6 years old, an incident that caused their mother to have a breakdown. Amber was a promising student but became involved with drugs as a teenager. "She was beaten down," says Overstreet. We didn't live the American [Dream] childhood. We watched our family struggle through alcohol addiction and sickness. It was after Amber got into debt in Florida that Overstreet bought her a plane ticket and brought her to New York, where she again spent a short time in rehab before falling back into drug use and prostitution. By the time the news broke in December that bodies had been found along the side of Ocean Parkway, investigators were already returning to the unsolved case of another young woman, Shannan Gilbert, who was also an online escort. Gilbert was last seen on the night of May 1, 2010, in Oak Beach, a gated community within a few miles of where the bodies had been dumped, fueling speculation that the cases were related. Gilbert had arrived in Oak Beach from New Jersey in a hired car at 2 a.m., according to the driver. The police later said she had come to meet a date. Three hours later, Gustav Coletti, a 75-year-old resident, says Gilbert pounded on his door, screaming, "Help me! Help me! Coletti opened his front door and Gilbert came inside. When he asked her what was wrong, "she just stood there," he says. As he was dialing 911, she ran out of the house and headed toward the water. Joseph Brewer, the owner of the house Gilbert was visiting, has denied that he had anything to do with her disappearance, telling NEWSWEEK, "I am 100 percent innocent." The police have said he is not a suspect. For the local community, the rising body count recalls the murder sprees of convicted Long Island serial killers Joel Rifkin and Robert Shulman. Between them, the two men - a landscaper and a postal worker - bludgeoned and dismembered more than 20 prostitutes in the same area during an overlapping period in the early 1990s. Now, as then, reports are circulating that two serial killers may be loose on Long Island - or possibly that one set of remains is a leftover of Rifkin's slaughter. Rifkin, in an interview from prison with a local newspaper, has denied any involvement. N.G. Berrill, a forensic neuropsychologist who has studied and interviewed Rifkin at length in prison, notes that when the victims are engaged in prostitution, the cases often turn cold. People disappear, and folks don't know the difference.