OAK BEACH, NY (CBSNewYork) – It’s been two years since four bodies were found along Ocean Parkway, launching a massive investigation into a suspected serial killer on Long Island.

On Dec. 11, 2010, police discovered the first set of human remains while searching for New Jersey prostitute Shannan Gilbert, who went missing months earlier.

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1010 WINS’ Mona Rivera reports 

The bodies of Amber Lynn Costello, Megan Waterman, Maureen Brainard-Barnes and Melissa Barthelemy were the first four of 10 bodies eventually found on Gilgo Beach between December 2010 and April 2011.

All were found along a seven mile stretch of Ocean Parkway.

Two years later, relatives say they’re frustrated that there have been no new leads in the case.

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“I haven’t seen very much progress,” said Waterman’s aunt Elizabeth Meserve. “I want to find her killer. I’m not even sure if all of the victims are from the same killer and it would be nice to have the unidentified to be identified.”

Last year, police released sketches of two of the unidentified victims. Among those is a female toddler, 18 to 24-months-old, who was found wrapped in a blanket along the highway.

Suffolk County Police released composite sketches of two of the victims found along Ocean Parkway (credit: Handout)

Suffolk County Police released composite sketches of two of the victims found along Ocean Parkway (credit: Handout)

Police said the toddler appeared to be the daughter of one of the unidentified women who was found seven miles away in Nassau County.

Gilbert’s remains were found on Dec. 13, 2011 in a marshy area on Oak Beach about a quarter-mile from where her cell phone, purse, jeans, shoes and lip gloss were found the week before.

Detectives believe Gilbert drowned when she was last seen running and screaming for help in Oak Beach back in May of 2010. The results of her autopsy classified her death as “undetermined.”

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Last month, her family filed a civil lawsuit against the last known person believed to have seen Gilbert alive.