"Based on the evidence, the facts, and the totality of the circumstances, the prevailing opinion in Shannan's death, while tragic, was not a murder and was most likely noncriminal," Suffolk County Police Commissioner Rodney Harrison said at a news conference.
Police then played a video that walked through what they believe happened and played parts of 911 calls made on the night Gilbert disappeared in March 2010.
In a call made by Gilbert, she says, "They're trying to kill me."
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Harrison has opted to gradually publicize previously unreleased pieces of evidence, hoping to reframe the case and, perhaps, jog memories.
911 calls made by two Oak Beach residents that Gilbert encountered that night -- Gus Colletti, who has since died, and Barbara Brennan -- were also played.
Gilbert is one of 10 women whose remains were found at Gilgo Beach.
Last month, investigators released new video and images of another victim.
The last known surveillance video of Megan Waterman was recorded at the Holiday Inn Express in Hauppauge in June 2010.
Suffolk County police say Waterman stayed at the hotel for a few days before leaving to meet with her killer. Her remains were found six months later.
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The new videos and photos are also available at GilgoNews.com.
The investigation into the Gilgo Beach murders started more than 11 years ago when Suffolk County Police officers discovered the body of Melissa Barthelemy along Ocean Parkway while searching for Gilbert.
On May 1, Gilbert, a Craigslist sex worker, traveled with her driver Michael Pak from Manhattan to meet a client, Joseph Brewer, in the Oak Beach Association.
Gilbert's driver remained in the area while she met with Brewer. During the meeting, Gilbert reportedly began acting irrationally, prompting her client to contact the driver to have Gilbert leave his home.
After Gilbert refused to leave the location, she eventually fled on foot into the Oak Beach community. Gilbert interacted with two additional homeowners within the community before disappearing.
Both Brewer and Pak were interviewed and cooperated with police and cleared of any criminal involvement in Gilbert's death.
The remains of 10 people were found in 2010 and 2011 in the weedy sections off Ocean Parkway near Jones Beach. At the time, police said half of the identified victims worked as prostitutes.
Earlier this year, Harrison created the Gilgo Beach Homicide Investigation Task Force, which includes representatives from the FBI, New York State Police, the Suffolk County District Attorney's office and the Suffolk County Sheriff's Office.
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