THE mom of the Gilgo Beach victim whose death broke the Long Island serial killing case wide open was murdered before she could ever see justice.

Shannan Gilbert’s mother Mari was heartlessly stabbed 227 times by her surviving daughter years before investigators arrested suspect Rex Heuermann.

Mari was well-known to the residents of Long Island, New York, as she was among the first to publicly propose that a serial killer might be at large following her daughter Shannan’s disappearance in May 2010.

Her disappearance came just months after the remains of four women, known as the Gilgo Four, were uncovered on the ill-fated shores.

The mother frequently appeared on local television to demand justice for Shannan, who vanished after fleeing from a client she had met through Craigslist for sex work.

During the search for Shannan, investigators discovered her remains along with five other bodies near the doomed shores, increasing the total number of bodies found to 10.

Because of Shannan, an urgent search for the Long Island Serial Killer began.

It’s unclear how Shannan died, and investigators don’t suspect that she was murdered.

However, seven of the other victims have been linked to Heuermann – a disgraced architect who lived on Long Island and ran a private firm in Manhattan.

But Mari never got to see glimmers of justice for those women, as the 52-year-old mom was murdered by her schizophrenic daughter, Sarra.

On July 23, 2016, Sarra came into Mari’s Catskills apartment, stabbed her mother over 200 times, and beat her with a fire extinguisher.

The daughter was found guilty of second-degree murder and was sentenced to 25 years to life in prison.

According to John Ray, an attorney who to this day represents Gilto Beach victims, Sarra was “hearing voices” when she lashed out at her mom.

He claimed that Sarra, who lived in a separate adjoining apartment, came over because she was hallucinating, WNBC reported in 2017.

The lawyer said the mom “died while trying to help her mentally ill daughter.”

‘BACKBONE OF THE FAMILY’

Sherre Gilbert, a surviving daughter of Mari, shared a heartwrenching message following her mother’s death.

In a Facebook post, she wrote, “So as a lot of you may know, my mother passed away yesterday,” TV Insider reported.

“She was murdered by my sister, Sarra who was battling a mental illness for 2 1/2 years.”

An emotional Sherre said that she and her sister Stevie were “devastated beyond words” after hearing the tragic news.

She described Mari as the “backbone of the family.”

In the Netflix docuseries Gone Girls: The Long Island Serial Killer, which premiered in March, reporter Robert Kolker suggested that Mari would still be fighting to this day if she were alive.

“She would not be convinced that Shannan’s death was disconnected from the others,” he said in the series.

CASE CONTINUES

Heuermann has been accused of murdering the Gilgo Four, Megan Waterman, Melissa Barthelemy, Amber Lynn Costello, and Maureen Brainard-Barnes, along with Jessica Taylor, Sandra Costilla, and Valerie Mack.

Though Mari met a tragic end in 2017, her attorney John Ray continues to voice his belief that the Long Island serial killer murdered Shannan.

Cops believe that she may have died of natural causes, but Ray claims there’s overwhelming evidence that she was killed.

“There’s so much existing evidence that has existed for years that’s been ignored by police – willfully ignored,” Ray told The U.S. Sun in 2023.

“There’s no reason to continue that willful behavior, so if it does continue, that if this part of the investigation continues to be ignored, then I know problems still exist in the police.”

Shannan’s story is being retold in the Peacock docuseries The Gilgo Beach Killer: House of Secrets, which is now streaming.

No trial date has been set for Heuermann. His next court appearance is scheduled for June 17.

Murder victims linked to the Long Island Serial Killer

The sleepy seaside community of Gilgo Beach in Long Island, NY, was horrified after the arrest of Rex Heuermann in July 2023 for a series of gruesome murders. Here is what we know about his alleged victims:

Maureen Brainard-Barnes, 25 – Brainard-Barnes was believed to be a sex worker based in Norwich, Connecticut. She went by the names “Juliana” or “Marie” and advertised her services on various platforms, including Craigslist and Backpage. She mostly worked out of hotels in Manhattan. On the day of her death on July 6, 2007, she took an Amtrak train from New London to Grand Central Terminal. She was reported missing eight days later, but it wasn’t until 2010 that her remains were found on the north side of Ocean Parkway near Gilgo Beach.

Melissa Barthelemy, 24 – Barthelemy was an aspiring hairstylist who was last seen alive on July 12, 2009. She worked as an online escort and lived in the Bronx, NYC, but primarily worked out of hotels in Manhattan. She used sites such as Adult Friend Finder and went by either “Chloe” or “VerySexyChloe” online. After she disappeared, her sister revealed she had received calls from a stranger who admitted to killing her. Her body was found on Gilgo Beach on Dec 11, 2010.

Megan Waterman, 22 – Waterman was a single mother living in Scarborough, Maine, when she went missing. A sex worker who advertised her services on Craigslist and Backpage used the aliases “Lexxy” and “Sexy Lexi.” She vanished on June 6, 2010, after leaving a Holiday Inn hotel located in Hauppauge, Long Island. Two days later she was reported missing, and her body was found on December 13 of that same year.

Amber Lynn Costello, 27 – Costello lived in West Babylon, Long Island, at the time of her disappearance. She advertised as a sex worker on Craigslist and Backpage, reportedly to support her heroin addiction. She had entered a detox program shortly before his disappearance before relapsing. She was last seen alive on September 2, 2010, and her body was discovered on Ocean Parkway on December 13, 2010.

Jessica Taylor, 20 – Taylor was an escort working in Midtown, New York when she was reported missing on July 19, 2003. She was reportedly spotted at the Port Authority bus terminal in Manhattan between July 18 and 21. On July 26, 2003, parts of her body were found in Manorville. More of her remains were discovered on March 29, 2011, during the search for Shannan Gilbert, a 23-year-old sex worker.

Sandra Costilla, 28 – Costilla was a native of Trinidad and Tobago living in New York at the time of her disappearance. Investigators called Costilla a “drifter” and her last known address was in Queens. Costilla’s remains were uncovered in the woods in Southampton on November 20, 1993. Costilla had numerous sharp force injuries to her face, torso, breasts, left thigh, and vaginal area.

Valerie Mack, 24 – At the time of her disappearance, Mack was working as an escort under the alias “Melissa Taylor.” She was last seen alive in the spring of 2000 in New Jersey, but her family didn’t report her missing. Parts of her body were discovered by hikers in September 2000 in the Long Island Pine Barrens, but she was not identified and was instead given the nickname “Jane Doe No. 6.” The rest of her remains were recovered on April 4, 2011, near Gilgo Beach.

There have been several other murder victims tied to a Long Island Serial Killer, but no connection has been found to Rex Heuermann, and he is not a suspect in their deaths.

Karen Vergata, 34 – Vergata was a sex worker living on West 45th St. in Manhattan at the time of her disappearance on Valentine’s Day, 1996. She had called her father that day to wish him a happy birthday. Parts of her body were found at Davis Park on Fire Island’s Blue Point Beach on April 20 that year, but at the time, she wasn’t identified and was known as “Jane Doe No. 7.” Her skull was found on Ocean Parkway on April 11, 2011.

Additional victims – Four other remains of possible victims were also recovered but have not been officially named.