Long Island Serial Killer: How Close Are Authorities to Catching the Killer — or Killers?

Nearly a dozen bodies — mostly of women — have been found on Gilgo Beach in New York. Are they connected? Subscribe to PEOPLE now for details of the Long Island Serial Killer, on newsstands now.

It seems the closest that anyone has gotten to catching the Long Island Serial Killer may be a phone call.

Little is known about whoever is responsible for the 10-plus bodies uncovered in recent years on Gilgo Beach in Long Island, New York. No suspects have ever been identified. But the victims’ friends and family do know this: The killer or killers like to taunt them.

A friend of Maureen Brainard-Barnes, the first of the victims to disappear, says she got an odd call a few days after the 25-year-old vanished in 2007.

“ said she was at a whorehouse in Queens,” Sara Karnes tells PEOPLE in this week’s issue, on newsstands now. “I told him she would never go for that, because she was independent. He goes, ‘Well, that’s where I saw her.’ And he described her to a T to me.”

Karnes, who passed her information on to the police, says the man she spoke to didn’t have an accent. “He definitely isn’t from New York, Boston or Maine, because those are the strongest places the accent comes out of. But he accentuated his S’s and his T’s. He spoke properly.”

Melissa Barthelemy vanished next, on July 12, 2009, and a series of calls came in after from her cell phone. Melissa’s younger sister, Amanda, answered. She thought it was Melissa, but she heard a man’s voice instead.

“He was tormenting her,” Melissa’s mom, Lynn, tells PEOPLE. “He was very calm. The last call he said he had killed her.”

Lynn says the man made the calls from Madison Square Garden and Times Square in New York City. “Most of the calls were in the evening,” she says, adding, “We thought maybe he lived somewhere else and works in the city and commutes.”

The last call was on Aug. 27.

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“When you start looking at taunting behavior attached to a serial murder case, it ratchets it up — you don’t see that with a lot of cases,” former FBI profiler Mary Ellen O’Toole tells PEOPLE. “It puts you at much higher risk of being apprehended. It is an added interaction.

“He is getting some kind of sadistic pleasure out of it. It would be horrifying. He is hearing her cry, he is hearing her fear. … Even after death, he is involved with them.”

Melissa and Brainard-Barnes were two of four escorts found buried in the same marshy, desolate area in Gilgo Beach in December 2010, all within about 500 feet of each other, strangled and wrapped in burlap. The other two bodies belonged to Amber Costello and Megan Waterman. They were uncovered accidentally as police searched for a missing 24-year-old escort named Shannan Gilbert.

Over the next four months, six more remains were found in the Gilgo Beach area, including the remains of a toddler and an Asian male, suggesting it might be a dumping ground for a serial killer or killers.

(Shannan’s body was found last. Police maintain that she likely died of natural causes after getting lost, though witnesses the night she disappeared say she was frantic and fleeing someone.)

O’Toole says that women, who each worked through Craigslist, seem to share more than just their resting place: “ contacts them and then he is in computer contact with them. He is manipulating them in three different ways — that is a lot of work.”

“He is a manipulator,” O’Toole says. “It is risky. One of these young women could become suspicious. That says a lot about him: This is part of his hunting behavior. That manipulation and the hunting process and his ability to control his women in his hunting process.”

While the foursome are likely linked, the connections between the other victims are more tenuous. They weren’t all killed the same way, and they don’t all match the same demographic profile.

WATCH: People Magazine Investigates Premiere Trailer — Long Island Serial Killer

Theories abound. The investigation continues. To this day, one of the Suffolk County Police Department’s “most highest-profile cases” remains unsolved — and a killer or killers remain at large.

“I wouldn’t call it frustrating. These cases do take time,” Suffolk County Police Chief Stuart Cameron tells PEOPLE. “There are a lot of investigative leads to go through. I can absolutely assure you that the cases are extremely high-priority, and we never stop working on it. I do believe that we’re making progress.”

In December 2015, Suffolk County Police Commissioner Tim Sini pulled the FBI into the investigation, and in February 2016, he launched a Gilgo Beach task force, assigning two full-time detectives from Suffolk County to focus only on the deaths, working side by side with FBI agents.

“We have a room dedicated to Gilgo,” Sini says. “It is very important to have a healthy dynamic and a lot of different perspectives. ”

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Can the case be cracked?

“I have reviewed all of the evidence in this case personally, and I am not going to hide behind any excuse this is unsolvable,” Sini says. “I have seen countless homicide investigations this solvable. Whether we solve it or not I can’t guarantee, but we will do everything we can to do it.”

The victims’ family and friends have accused law enforcement of incompetence and not caring about the case because some of the women were escorts.

“We absolutely do care,” Chief Cameron says. “We want to solve these cases. We know these girls have families, and we want to bring whoever did it to justice. So that criticism is completely unjust.”

Sini says investigators “have been tortured by this case, and they are doing everything they can to solve it.

“We are not closing this,” he says. “The task force will become dissolved when we have our suspect in custody.”

The families hope.

“It is like chasing a ghost,” Costello’s sister, Kim Overstreet, tells PEOPLE in this week’s issue. “I am hoping in my lifetime I find closure to it, if I ever can find closure. I don’t know if there is such a thing as closure when it happens.”