ALBUQUERQUE, N.M. — Jennifer Lannon loved her children, though she lost custody of them because of her struggle with prescription drug use. Just about a year before the mother of five went missing, she posted a heartfelt message to her daughter on social media for her sixth birthday, calling her unforgettable, sweet, sassy and smart.

“Somehow you were able to learn early on that life is too short to take it for granted. Thank you for reminding me when I forget so easily,” Lannon wrote.

The decomposing body of the 39-year-old mother and those of two of her troubled friends — Jesten Mata, 40, and Matthew Miller, 21 — were found this month in a pickup truck at the Albuquerque airport. With them was the body of Randal Apostalon, a man known to give rides for money.

The gruesome discovery at the parking garage — about 80 miles from the tiny town where Lannon, Mata and Miller lived — touched off a nationwide manhunt for Lannon’s ex-husband in a strange case stretching from New Mexico to New Jersey that raised questions about possible serial killings and left grieving loved ones trying to understand what happened.

Sean Lannon, 47, was arrested in St. Louis and charged with the beating death of a man in New Jersey he said sexually abused him as child. Authorities have not said why Lannon was in Missouri, but they revealed that he claimed he had killed a total of 16 people in New Mexico, including the four found at the airport.

Lannon was charged Friday with killing his ex-wife and two others in New Mexico.

They are investigating his claims but have said there are no missing people or other police reports to indicate additional victims.

On Thursday night, a man wanted for questioning in the disappearances of Jennifer Lannon, Marta and Miller was arrested on a warrant in Albuquerque. The city's police department said 45-year-old Daniel Lemos was taken into custody by the U.S. Marshals Service.

Sean and Jennifer Lannon lived in New Jersey before moving to New Mexico a few years ago — before he filed for divorce.

Court records related to the couple’s divorce and custody case showed that Sean Lannon was awarded sole custody of the couple’s three children in 2019 and that a protective plan from the New Mexico Children, Youth and Families Department included only supervised visitation by their mother over concerns at the time about the potential for neglect due to prescription drug abuse.

Relatives say Sean Lannon flew to New Jersey in early March with the couple’s three children — 6- and 7-year-old girls and a 4-year-old boy. He took them to his parents’ house and left again, saying he was going to look for his ex-wife, whom he claimed had run off with friends. Her family became worried, saying it wasn’t like her to be without her children.

Meanwhile, those who loved the three friends from the town of Grants are searching for answers.

The trio had their share of struggles with substance abuse, according to authorities and court records.

Police Lt. David Chavez said Miller “had his demons” — an addiction to opioids that led to run-ins with officers over minor offenses like loud music and traffic violations. He described Miller as a decent guy who was fond of his pets.

Miller would never leave his dogs and cats, so when he had not been home for some time, something had to be wrong, authorities said. Police began investigating in late January and learned Jennifer Lannon and Mata also were missing.

It had been a rough year for Miller. His father died in January 2020, only to be followed by his grandparents and mother.

His maternal grandmother, Juanita Shult, said Miller was mixed up with the wrong people and she couldn’t get through to him about not using drugs. She said Miller couldn’t work because of a health issue with his brain and sometimes couldn’t keep the utilities on. He would drive to her home to fill buckets of water, shower or ask for money.

“I know this hit Matthew hard,” she said of the string of deaths in his family. “I didn’t want to make any excuses for him. But he didn’t deserve this. Nobody did. He has two little sisters that are brokenhearted over this.”

Shult said she has days when she feels like she failed as a mother and grandmother, when she’s sat in the car sobbing and when she imagines her daughter and grandson together in heaven.

Miller’s remains were still being held as evidence, with autopsy results pending. When his body is released, Shult plans to have him cremated and place his ashes next to his mother.

Mata had talked about making changes in his life, for his 17-year-old son with an ex-girlfriend and for the children of his fiancée, Leony Calzada.

Calzada said Mata was sweet and good with children, especially her 5-year-old son, Jayden, who considered Mata his best friend. Mata had trouble finding work in Grants because of the time he spent incarcerated on charges ranging from shoplifting to drug trafficking, and Calzada said people didn't give him a chance.

“Everyone has their faults,” she said. “He was a real nice person. He would help anybody.”

The ex-girlfriend, Hilary Sweeney, met Mata in high school in the Arizona mountain town of Show Low where Mata's family still lives. She was drawn to the tall, handsome guy with a great smile who would wrap his arms around her like a security blanket. They were together for several years.

Sweeney would send Mata coloring pages, school assignments and pictures of Ryan to keep in touch when he was locked up. It had been years since she saw Mata in person, but she said they talked last year about him getting to know his son and getting his life straight.

“I told him, 'I want you to be happy. I don’t want you to worry about Ryan and I financially. I made it to where I already know, you need to take care of you and focus on you and get better so you can be part of Ryan’s life,’" Sweeney said. “That was the plan, and things didn’t go as planned.”

Separate from the friends, Apostalon was likely in the wrong place at the wrong time when he was killed, Albuquerque police said. They confirmed Wednesday that he died by blunt force trauma but didn't release other details.

The 60-year-old from Albuquerque had no criminal record. After some financial trouble, Apostalon had been working odd jobs.

Chavez, the Grants police lieutenant, has been tightlipped about what might have led to the killings but says drugs were not the main motive. He describes it as a complicated case.

As is life.

Jennifer Lannon's family remembered her as a beloved daughter, sister, friend and most important, a mom. She provided a glimpse into her life via social media with posts about resilience and understanding herself better after a rough patch.

She described life last summer as low key and happy.

“... just learning to focus on little moments together as a family," she wrote, "and reminding everyone that we don’t get time like this to really be together often so don’t take it for granted!”

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