Amherst, N.Y. - The teenage sister of one of four prostitutes found slain on Long Island received a half-dozen calls from the victim's cell phone in the six weeks after she disappeared in 2009, her family said Thursday.

Melissa Barthelemy's sister, Amanda, who was then 15, got the first call from an unidentified man a few days after Barthelemy was last seen in New York City on July 12, 2009, said their mother, Lynn, and her fiance, Jeff Martina.

They said the last call came on Aug. 26, soon after they told a Buffalo TV station about the calls.

The pair said police advised them not to reveal the contents of the calls, which they described as crude.

"It's nothing that we can say on the air," said Lynn Barthelemy, whose youngest daughter stood in a corner crying at the family's lawyer's office in suburban Buffalo. "It wasn't nice, it wasn't nice."

"You can see her (Amanda's) condition right now in the room, it just had a devastating effect," added Martina as he glanced back at the 16-year-old. "The content of the calls were horrible."

A law enforcement official has told The Associated Press the caller referred to Barthelemy in the first call as a "whore."

The bodies of Barthelemy and three other prostitutes were found dumped on a desolate stretch of beachfront on Long Island in December. Police officials suspect the slayings were the work of a serial killer. They have not specified yet how the women were killed.

On Monday, Suffolk County officials identified Barthelemy's body and those of two other women, Maureen Brainard-Barnes, of Norwich, Conn., and Amber Lynn Costello, of North Babylon. The body of Megan Waterman, of Scarborough, Maine, was identified last week.

Barthelemy, 24, a trained hair stylist, moved to New York City in 2007, worked at a barber shop and later was hired as an exotic dancer, her mother said. She said the family didn't realize until after her disappearance that she had turned to prostitution.

"We were upset, but she's still our daughter and she's a wonderful person," she said. "Melissa was a good girl and somebody manipulated her into doing this and scared her."

Barthelemy had dreams of returning to Buffalo someday and opening a hair salon, and she was happily anticipating a visit from her little sister the weekend after she vanished. "I mean, thank God this didn't happen when (Amanda) got there - I mean, I could have lost both of my daughters," their mother said.

"We want to get justice," she added. "And we'd like to get it out there to these girls that are working in that type of profession, don't think you can't go home to your parents because there's something called unconditional love. You can go home no matter what happens.''

Barthelemy had a very loving family who were in constant contact with her, and she was working as an escort "to supplement her income from hairstyling to pay her rent," said the family's attorney, Steven Cohen. "She wasn't in it for very long. She was not heavily entrenched in this lifestyle."

Barthelemy's family faulted the police for delaying the initial search for her. But New York City police said they had begun to track her cell phone signal within a week of her being reported missing.

"Missing persons launched an intensive investigation as soon as they received the case," chief NYPD spokesman Paul Browne said Thursday.

Police tracked the signal to midtown Manhattan and searched areas near Pennsylvania Station and the Port Authority bus terminal, but the signal went dead, according to an official who had direct knowledge of the case but was not authorized to speak publicly and spoke on condition of anonymity.

Later, cell phone records obtained through a court order showed a call to her voicemail was made in Massapequa, a hamlet not far from where her body was found, on the day she went missing, the official said.

Investigators canvassed nearby hotels, restaurants and the beachfront. Later, detectives gave Barthelemy's toothbrush to the Suffolk County police in the hope of identifying her, and eventually turned the thick case file over to the police department there.

They also discovered another phone once belonging to Barthelemy and tracked it to a convict who said he picked up the phone after she dropped it in a fight with another woman. Authorities in New York also located Barthelemy's pimp, who corroborated the man's story, saying he had ordered the other woman to fight Barthelemy because he was upset she had been seeking clients on her own, the official said.

Associated Press writer Colleen Long in New York City contributed to this report.