The long-haunting case of the "Long Island Serial Killer," linked to the tragic deaths of eight women, appears poised for a resolution with Rex A. Heuermann, 62, of Massapequa Park, expected to change his plea to guilty during a hearing. This significant development marks a potential end to a nearly two-decade-long mystery that has captivated the region. Presiding over this high-profile case is State Supreme Court Justice Timothy P. Mazzei, whose extensive legal career has now placed him at the center of deciding an alleged serial killer's fate.

Heuermann, who owned a Manhattan architectural consulting business, was arrested in July 2023. Since his arrest, he has been charged with the murder in the deaths of seven women, and Newsday recently reported that he plans to plead guilty to an eighth homicide, that of Karen Vergata, which law enforcement officials have long linked to the murders. While Heuermann has publicly denied involvement in the killings, his anticipated guilty plea would bring a long-awaited conclusion for the victims' families.

Justice Timothy P. Mazzei brings a formidable background to the bench, having served as a veteran prosecutor in the Suffolk County District Attorney’s Office, where he handled numerous murder cases, including the infamous 1979 killing of 13-year-old John Pius. After nearly a decade as a prosecutor, leaving as bureau chief of the Homicide Division, Mazzei entered private practice and later served on the Brookhaven Town Board before being elected a judge in 2015. His career reflects a deep engagement with the legal system and a reputation for handling headline-grabbing cases.

Known for his acerbic style, quick temper, and unwavering demand for promptness and preparation, Justice Mazzei is regarded by colleagues and attorneys as one of Suffolk's judiciary's sharpest legal minds. Defense attorney Anthony La Pinta described him as "the hardest-working judge in Suffolk County" who "demands the highest standards from lawyers." Mark Lesko, a former acting U.S. attorney, praised Mazzei as a "fair judge" with "crazy" work ethic, noting his ability to manage a demanding trial caseload and navigate complex legal issues, which was crucial for the Gilgo Beach case to avoid "dozens of rabbit holes." Mazzei’s 2025 ruling, which allowed prosecutors to present advanced DNA techniques against Heuermann—a first in New York State—set a significant precedent for the case.

Among the victims is Melissa Barthelemy, a Buffalo native who moved to New York City in 2007 to pursue cosmetology but eventually worked as an escort. Described as independent and close to her sister, Amanda, Barthelemy regularly communicated with her family. She was last seen on July 12, 2009, when she told a friend she was meeting a client. In the weeks following her disappearance, Amanda received a series of "taunting" calls from an unknown man, now believed to be Heuermann, using Melissa’s phone. Her remains were discovered wrapped in burlap along Ocean Parkway near Gilgo Beach on December 11, 2010.

Megan Waterman, a native of Scarborough, Maine, turned to sex work to support her daughter, Liliana. She advertised her services using names like Lexxy and Sexy Lexi. Last seen on June 6, 2010, boarding a New York-bound bus with her then-boyfriend Akeem Malik Cruz (described by police as her pimp), Waterman was staying at a Hauppauge hotel when she left to meet a client at 1:30 a.m. Her family reported her missing after she uncharacteristically failed to check on her daughter. Her remains were later found along Ocean Parkway, part of the group known as the "Gilgo Four."

Amber Lynn Costello, originally from North Carolina, experienced a difficult early life, marked by dropping out of high school and developing a heroin addiction. She worked as a sex worker, advertising on Craigslist and Backpage as Carolina or Mia. Court records indicate Costello had a ruse where she would meet clients at her home, and after payment, a roommate would pretend to be her boyfriend to make the client leave before sex. Prosecutors state she used this ruse on Heuermann in early September 2010. Costello, then 27, was last seen on September 2, 2010, leaving her West Babylon home to meet a client, believed to be Heuermann, agreeing to leave her phone and purse for enough money. Her remains were found three months later in brush off Gilgo Beach.

Maureen Brainard-Barnes, from Groton, Connecticut, was a bookish young woman who published poetry and invented games for her children. Despite earning straight A's in high school, she became a single mother at 17, struggling to support her two children. She was introduced to prostitution through a modeling job in Manhattan after being laid off from a telemarketing job and facing eviction. Advertising as Juliana or Marie, she left her children with their fathers on July 6, 2007, for Manhattan. She was last heard from on July 9, 2007, calling a friend to say she was going to meet a client on an "out-call." Her family suspected her death when she missed her brother's funeral, a stark departure from her usual contact with loved ones.

Jessica Taylor grew up in Poughkeepsie, loving dancing, drawing, and spending time with her family. Her mother described her as hardworking at school and passionate about working with children, lamenting that she never had her own. Taylor, 20, spoke to her mother on July 21, 2003, planning a birthday visit. She was last seen at the Port Authority bus terminal in Manhattan. Her partial remains were found on July 26, 2003, in Manorville. More of her remains were discovered near Gilgo Beach in 2011. Taylor was a sex worker in a relationship with a man believed to be her pimp. Her remains were identified, in part, by a tattoo ("Remy's Angel") on her right hip, which Heuermann allegedly "severely obliterated" to prevent identification.

Sandra Costilla, a native of Trinidad and Tobago, with a police officer father, is believed to be Heuermann's first victim. Little is known about her early life or family. Described as a "drifter," her last known address was in Ridgewood, Queens. Her partially clothed body was discovered by hunters in the woods of North Sea in Southampton on November 20, 1993. Authorities stated Costilla, 28, was strangled, stabbed, and possibly raped. Her identity was confirmed by fingerprints from a 1992 subway turnstile arrest. Initially, her murder was not linked to Gilgo Beach and was suspected to be the work of John Bittrolff. However, investigators later matched Costilla's DNA from hairs found on her body to DNA recovered from Heuermann, definitively linking her case to him.

Valerie Mack faced a challenging childhood, including multiple adoptions after her birth mother died of AIDS. After giving birth to a son in high school, she developed a drug addiction. She moved to Philadelphia, where she was arrested on prostitution charges and worked as an escort under the name Melissa Taylor. Mack, 24, vanished without apparent ties to Long Island and was not reported missing. Her remains were found near a Manorville sump discharge basin on November 19, 2000. Other parts of her body were discovered off Ocean Parkway in April 2011, leading to her killing being linked to the Gilgo Beach victims and her positive identification through genetic genealogy.

Karen Vergata, raised in Glen Head, was a quiet art-interested student who later struggled with drug use, leading to arrests and rehab. She also worked as an escort. She had two children, Gary Doherty and Eric Doherty, with a married man, Guenther Hugo Lind. Her family last heard from her on Valentine's Day in 1996. Vergata's dismembered remains were found in 1996 on Fire Island, and her skull was discovered in 2011 near Jones Beach. Identified in 2025 through genetic genealogy as a Gilgo Beach victim, Vergata was 34 at the time of her death. Although not formally charged, Heuermann is expected to plead guilty to her homicide, as reported by Newsday.

Justice Mazzei's rigorous approach to the Heuermann case, particularly his groundbreaking decision to allow advanced DNA techniques, proved instrumental in solidifying the prosecution's evidence. This ruling not only shaped the outcome of this specific investigation but also established a new legal precedent in New York State for using cutting-edge forensic science in criminal proceedings.

The expected guilty plea from Rex A. Heuermann, under Justice Mazzei's purview, marks a pivotal moment for the Long Island community and, most importantly, for the families of Melissa Barthelemy, Megan Waterman, Amber Lynn Costello, Maureen Brainard-Barnes, Jessica Taylor, Sandra Costilla, Valerie Mack, and Karen Vergata. This long and arduous journey for justice appears to be culminating, offering a measure of closure for those who have mourned their loved ones for far too long.