Dateline investigates the murders of several women found dead along Gilgo Beach in Long Island, New York.During The Hunt for the Gilgo Beach Killer, Heuermann's former neighbor Jimmy Mack speaks out in his first TV interview, telling Dateline that he "immediately" had a bad feeling about Heuermann. Additionally, Mack revealed that they had a "confrontation" after Heuermann allegedly threatened to cut the tires of a car in Mack's driveway that partially blocked the sidewalk.The special also examines the death of Shannan Gilbert, whose remains were found on Gilgo Beach in December 2011. Speaking out for the first time since Heuermann's arrest, Shannan's sister calls for Suffolk County Police Department to reopen her sister's case.