The investigation at Gilgo so far

The beginning

In December, Suffolk police looking for a missing Jersey City woman discovered a burlap-wrapped skeleton in Gilgo Beach. Since then, seven more decomposed bodies and sets of bones have been uncovered in brush along the South Shore barrier island in the county. Only the first four -- all women in their 20s who worked as prostitutes and who disappeared while meeting clients -- have been identified. Police believe they are the victims of a serial killer.

In the first hours of a search into Nassau County on Monday, police found a plastic bag of human bones and, separately, a human skull, near Jones Beach. The finds bring the potential number of victims to 10. Investigators theorize that more than one killer may be responsible, sources tell Newsday.

The missing woman whose search triggered the case -- Shannan Gilbert, 24 -- has not been found.

The investigators

The expanding criminal investigation now involves Nassau and Suffolk County detectives and prosecutors, NYPD investigators, and state and park police. A team of FBI serial killer profilers based in Quantico, Va., has prepared character studies of potential suspects. FBI experts, both Long Island medical examiners and the city medical examiner are also conducting genetic analysis and forensic anthropology.

The search

In Suffolk, authorities have repeatedly canvassed a 71/2 mile stretch adjacent to Ocean Parkway, from Oak Beach west to the Nassau line. The search through nearly impenetrable brush involving dozens of officers, cadaver dogs and helicopters was unprecedented in scope in the history Long Island law enforcement.

An extensive search over frozen ground in December failed to find four sets of remains recovered in March and April. Suffolk marine bureau divers have also searched Hemlock Cove, between Oak and Gilgo beaches, and areas of the inlet in the Oak Beach area. Authorities have searched along the parkway from the county border west to the tower at Jones Beach State Park.

The FBI will provide aircraft to do aerial imaging of the entire length of Jones Beach Island to look for more remains.

Timeline of case so far 

May 1, 2010

Shannan Gilbert, who advertised as an escort on Craigslist, runs from the Oak Beach home of a client and vanishes. Her disappearance prompts police to do a limited search in and around the beach community. Both the client and Gilbert's driver are interviewed.

Dec. 11

A Suffolk cop working with a cadaver dog finds a skeleton several feet north of Ocean Parkway in Gilgo Beach, about 4 miles west of Oak Beach.

Dec. 13

Three more sets of remains are located nearby. Like the first, they are wrapped in burlap and left unburied. Police believe the four are likely victims of a serial killer.

Dec. 16-17

After Gilbert is ruled out as one of the bodies, an expanded search using more than a dozen cadaver dogs turns up no more remains or significant clues.

Jan. 24

Officials identify the victims as Maureen Brainard-Barnes, 25, of Norwich, Conn.; Melissa Barthelemy, 24, of the Bronx; Megan Waterman, 22, of Scarborough, Maine; and Amber Lynn Costello, 27, of North Babylon. Like Gilbert, the women worked as prostitutes and advertised on Craigslist.

January

In the days after Melissa Barthelemy vanished on July 12, 2009, a man made six calls from Barthelemy's cell phone to her teenage sister, a law enforcement source told Newsday. New York City police determined the calls were coming from midtown Manhattan, but the caller didn't stay on the line long enough for police to find him.

February-March

Suffolk police say they return periodically to Ocean Parkway to search.

March 29

A fifth set of remains is discovered off the parkway, east of the previous finds. 

April 4

Three more sets of decomposed remains are recovered, bringing the total to eight. Newsday later learns one is a child wrapped in a blanket. Another consists of a human head in a plastic bag. A third shows clear signs of dismemberment.

April 6

State and Nassau police announce they will search west into Nassau County beginning April 11. 

April 11

A state trooper finds human bones in a plastic bag less than 40 feet from Ocean Parkway on state-owned land, about 1.5 miles east of the Jones Beach tower. About four hours later, a Suffolk officer and a cadaver dog find a human skull west of Tobay Beach. A source said a preliminary analysis of the skull suggests it is of a woman, but likely too old to be Gilbert.