“Secrets by the Bay”: Dateline Reports on Elizabeth Sullivan Homicide August 16 2025

On Saturday, August 16, 2025, Dateline NBC airs a gripping Weekend Mystery episode titled “Secrets by the Bay”, reported by Keith Morrison. This haunting story revisits the 2014 disappearance of Elizabeth Sullivan, a young San Diego mother whose vanishing would baffle investigators for nearly two years—until her body was discovered in the bay, and her husband was charged with murder. The episode dives deep into the disturbing details of the investigation, the courtroom drama, and the secrets that surfaced from beneath the waves.

The Disappearance of Elizabeth Sullivan

Elizabeth Sullivan, a 32-year-old Navy wife and mother of two young daughters, was last seen alive on October 13, 2014, in San Diego’s Liberty Station neighborhood. Her disappearance followed a frantic phone call to her best friend, Calandra Duckett, in which Elizabeth voiced fear for her life, saying her husband had threatened to kill her. She was never heard from again.

In the immediate aftermath, her husband Matthew Sullivan told police and friends that Elizabeth had left on her own accord, possibly seeking a fresh start. A suitcase was missing, and he pointed to a $1,000 withdrawal she had made as evidence that she had walked away. Elizabeth’s friends, however, remained unconvinced. She left behind her daughters—something those close to her said she would never have done voluntarily.

A Breakthrough Nearly Two Years Later

Despite repeated pleas and ongoing investigation, the case went cold for nearly two years. Then, on October 6, 2016, a decomposing body was found floating in San Diego Bay—just half a mile from the Sullivans’ former home. That same day, Matthew Sullivan was in the process of moving across the country with a new girlfriend. Though initially unconfirmed, the remains were soon identified as Elizabeth Sullivan. The medical examiner ruled the death a homicide, revealing she had been stabbed and suffered blunt force injuries, including a broken jaw.

Strangely, the examiner believed she had been dead for only a month or two—raising questions about where her body had been kept all that time. Prosecutors would later argue that Matthew had hidden her body in a freezer before disposing of it just before his cross-country move.

The Investigation Zeroes In on Matthew Sullivan

Suspicion quickly turned to Elizabeth’s husband. Although Matthew had cooperated with early police efforts—including a polygraph he passed—investigators found his behavior increasingly troubling. He never filed a missing person’s report; that was done by one of Elizabeth’s friends. Police also discovered that on the day of her disappearance, Elizabeth had paid for a meeting with a divorce lawyer using his credit card—a move that Matthew noted in a 911 call as suspicious.

Forensic teams found evidence of blood beneath the cleaned carpet in Elizabeth’s bedroom. Luminol revealed stains on the subfloor and padding. The most incriminating discovery came later—when authorities searched the attic of the home and found a bloodied military-style folding knife with DNA from both Elizabeth and Matthew. Police believe this was the murder weapon.

The Trial and Conviction of Matthew Sullivan

Matthew Sullivan was arrested in Delaware in January 2018 and extradited to San Diego. His trial began in February 2020. Prosecutors laid out a case of domestic violence and betrayal, suggesting Matthew acted out of rage after learning Elizabeth was having an affair and intended to leave him, taking their daughters with her.

Deputy District Attorney Jill Lindberg presented forensic evidence, including the knife and blood traces, and pointed out that Matthew bought carpet cleaner the day after Elizabeth’s disappearance. The prosecution argued he killed her, cleaned the scene, stored her body in a freezer, and disposed of it in the bay when he was preparing to move.

Sullivan’s defense attorney, Marcus DeBose, painted a different picture—claiming Elizabeth had a history of self-harm and emotional instability, and that the blood in the bedroom could have been the result of cutting. He also argued that the freezer theory was pure speculation.

After just over a day of deliberation, the jury found Matthew Sullivan guilty of second-degree murder. He was sentenced in March 2021 to 16 years to life in prison. During sentencing, Sullivan showed no remorse, instead complaining about not being allowed to call certain defense witnesses. The judge strongly rebuked his lack of accountability, describing the murder as brutal and calculating.

Aftermath and Impact

For Elizabeth’s friends and family, the verdict brought long-awaited closure. Her godsister, Calandra Duckett, gave an emotional statement during sentencing, condemning the “demonic act” that took her loved one. Another friend, Nathan Caracter, spoke directly to Sullivan in court, expressing heartbreak and frustration.

Detective Kim Collier, whose relentless work helped crack the case, revealed that finding the murder weapon was a pivotal moment in the investigation. Her determination ensured Elizabeth’s voice was not silenced forever.

Dateline’s “Secrets by the Bay” offers a detailed account of this devastating case, exploring the complexities of domestic violence, mental health, and deception behind closed doors. With powerful interviews and meticulous reporting, Keith Morrison guides viewers through a mystery that spanned years and left a lasting scar on a family and community