Mom of 2 Vanishes After Harrowing Phone Call with Best Friend: "He's Gonna Kill Me"

Over their lengthy friendship, Calandra Duckett shared many phone calls with best friend Elizabeth “Liz” Sullivan — but their final call still haunts her to this day.

A terrified Liz called Duckett in the middle of the night on Oct. 13, 2014 in the midst of a heated argument with her husband, Matthew Sullivan. 

“She sounded frantic,” Duckett told Dateline: Secrets Uncovered. “They were arguing and she said this [expletive] is talking about he’s gonna kill me and I was half asleep, but I know that I told her lock yourself in your room, we just have to get to morning and she said hold on a sec, hold on, I think he’s coming.” 

Liz hung up the phone and Duckett waited for her friend to call back, but she never did. 

Liz mysteriously vanished from her San Diego home, leaving behind her two young daughters. Matt insisted his wife, who was known to be impulsive, packed a suitcase and left, striking out to live a new life on her own.

But two years later, Liz’s grim fate would finally be discovered with the help of her friends and a dedicated detective determined to find the truth.

Who was Elizabeth Sullivan?

By all accounts, Liz was a “very complicated” person. She was vibrant, funn,y and often the life of the party. 

“She was completely brilliant,” Duckett said. “She was almost an unacknowledged genius.”

The friends first met when they were both in their 20s living near Norfolk, Virginia, the home of the largest Naval base in the United States. 

Elizabeth Sullivan Photo: San Diego Police Department

“She was very infectious,” Duckett recalled. “Elizabeth had a very eclectic personality.” 

But there was another side to Liz, too. The  woman who loved to laugh and connect with others had been diagnosed with Borderline Personality Disorder and could be impulsive, anxiety-ridden, or embrace a sort of manic enthusiasm. 

When she met Matt Sullivan, a Minnesota native enlisted in the Navy, Liz believed she had found someone to offer her stability and opportunity. Just a few months after they met, the pair got engaged. 

“I think they got married so fast because he was having a good time, she was having a good time. It seemed like a perfect match,”’ Duckett said.

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The newlyweds packed up their things and moved across the country to San Diego, California, where Matt had been stationed, to begin a new life together. They learned that Liz was pregnant, but just as the couple was settling into their new home, Matt was deployed overseas. 

What problems did Matt and Liz Sullivan have in their marriage?

Isolated in a new town, Liz gave birth to her daughter. They quickly had another daughter on the heels of the birth, as Matt continued to navigate long deployments. Liz settled into life as a pseudo-single mom and met close friend Nathan Caracter.

“The first thing that drew me to her was her sense of humor and she was smart, you know, I liked that,” he recalled. “She went to school, but eventually — eventually I really began to love Liz because I didn’t feel that I had to hide anything of myself from her and she wouldn’t judge me because we both knew that we had our flaws, and it was the first person I felt really comfortable admitting stuff like that to.” 

Matt returned home and the couple settled down in Liberty Station, but cracks soon began to emerge in the  marriage. Liz, who by now was used to doing things her own way, struggled to acclimate to having her husband back and the couple seemed overwhelmed by the responsibilities that came with having two young children.

“She saw all these opportunities for her and them and … he was content where he was in life,” Caracter explained. "You know he didn’t really want to explore or do much outside of work, go home, work, go home. That wasn’t cutting it for Liz.”

Who was Liz Sullivan’s boyfriend? 

Amid the strain in the relationship, Liz joined Tinder and began secretly dating Steven Sutton. 

 “He was a good-looking guy,” Caracter recalled. “He had aspirations and goals and, like, you know, he wanted to better himself, and he was educated and they could talk and it was all the things Matt wasn’t.” 

Liz often spent time with Sutton and his roommate, but his roommate’s girlfriend didn’t like her and called Child Protective Services one day after incorrectly assuming Liz might be leaving her children at home alone during her visits to her boyfriend.

CPS investigated and found no evidence of any misconduct, but they told Liz they would have to notify her husband of the phone call — and Liz realized her clandestine relationship would be revealed. 

That night, she told Matt the truth about the relationship. Matt would later tell authorities that he took the news in stride because the couple was living “separate lives” at that point. 

“Based on his interview, while surprised … he didn’t come across as that bothered by it,” Det. Kim Collier said.

Yet text messages between Matt and Sutton revealed something else. Matt seemingly taunted Sutton in the weeks leading up to Liz’s disappearance.

“Liz will need a place to stay soon,” he wrote in one. 

“I forgot to mention earlier I work at a hospital if you need help getting that STD cleared up,” he wrote in another.

When did Elizabeth Sullivan disappear? 

Then, on Oct. 13, 2014, Liz vanished after making that harrowing phone call. Investigators looked into both men in Liz’s  life around the time she disappeared. 

Matt was extremely cooperative with police. He agreed to let authorities search the couple’s house and took — and passed — a lie detector test. Sutton, on the other hand, quickly hired an attorney and refused to talk to police.

“The husband was cooperative and the boyfriend was not,” Collier said.

Although Sutton’s refusal to cooperate with police may have stalled the investigation, he was eventually cleared in the case.

Investigators also considered the possibility that, like Matt suggested, Liz just decided to walk away from her life to get a fresh start. They even found a journal where she wrote about a fictional woman with many parallels to her own life, who walked away from her family to start a new life. Liz also transferred around $1,000 from the couple’s joint bank account into her own private account just before she disappeared. 

Authorities also considered the grim possibility that maybe Liz had taken her own life. According to Collier, Liz had been known to engage in self-harm before as a  “cutter” who made superficial cuts to her body to relieve the psychological pain she was feeling inside.

When was Liz Collier’s body discovered? 

Detectives finally learned Liz’s fate when her body washed up along a San Diego bay two years later, less than half a mile from her home. The medical examiner would determine that her death had been a homicide.

“Essentially, she had been stabbed with a sharp object, enough to cause damage to some of her bones,” Collier said, adding that she also suffered a broken jaw.

Who Killed Elizabeth Sutton?

The body appeared the same day movers arrived to bring Matt to Maryland, where he planned to live with his new girlfriend, a fact that Collier found to be “very suggestive.” 

Although the medical examiner determined it appeared as though Liz had been killed just one month earlier, they also noted that the decomposition process may have been stalled if Liz had been stored in a freezer. Collier believed Matt may have gotten rid of the body before he moved, hoping it might wash out to sea. 

With him out of the house, detectives thoroughly searched the home. Using Luminol, they found evidence of blood in the master bathroom of the home and found large bloodstains in the bedroom on the carpet’s padding and subfloor, although the carpet itself had already been thoroughly cleaned. 

Authorities also learned that on the day Liz disappeared, she met with a divorce attorney and paid for the meeting using Matt’s credit card — something he noted himself during a bizarre call he placed to 911 that day.

“Hi. I have concerns my wife is trying to … have me — I don’t know, evicted or arrested from my house, and take my children away from me,” he told the dispatcher. “I mean, she took my personal credit card, used it to hire a lawyer against me.” 

Yet even with the evidence they had against him, the district attorney still didn’t believe it was enough to support charges against him. 

That’s when a determined Collier searched the property again, this time tearing up the insulation in the attic. She discovered a military-style folding knife hidden in the attic. Liz’s blood was found on the blade along with a mixture of DNA from Liz and Matt on the handle of the weapon.

“I actually cried,” Collier confessed. “You know, you work a case that long and you’re like, ‘this is it’ so it was a very good moment for me.”

Where is Matt Sullivan today? 

With all the evidence finally in place, Matt was arrested and charged with murder. Prosecutors believed he killed his wife after discovering she planned to leave him, then hid her body in a chest freezer in the garage for years until he had to move and get rid of the body.

He was convicted of second-degree murder and sentenced to 16 years to life in prison. Matt has continued to insist from behind bars that he did not kill his wife.

“No absolutely not, that’s crazy,” he told correspondent Keith Morrison. “I’ve never laid a finger on her, I’ve never hit her, nothing like that.”

For Collier and Liz’s friends, the verdict finally brought a measure of closure.

“I was so happy,” the detective said. “Elizabeth got justice and her husband didn’t get away with it.”