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The life that Florida teacher Denise Hallowell shared with her son Carlos Hallowell was filled with epic vacations, academic achievements, and proud moments embracing on the football field — but the once-enviable bond between them was irrevocably shattered in July of 2019.
As Denise napped in their idyllic lakeside home in Inverness, Florida, Carlos, then 17, snuck into her room while wielding an ax and plunged it into the back of her head.
The teen then called 911, claiming an intruder had broken into their home and attacked his mom.
“Hello?… I — I need someone, fast,” Carlos told the dispatcher in a recording obtained by Dateline: Secrets Uncovered that was played in the true crime show’s “Horror at the Lake” episode.
The investigation that followed would expose family secrets and reveal how the pair’s once picture perfect life had turned deadly.
Who was Denise Hallowell?
For generations, Denise Hallowell’s family had retreated to their peaceful home in Inverness to spend vacations along the lake. It’s where, as a child, she met neighbor Amy Alford.
“I’ve known Denise all my life,” Alford told Dateline. “She was about five years older than me, so she was like a big sister. I admired her.”
After spending her childhood exploring the lake, soaring through the air on a makeshift swing, and fishing off the dock, Denise went on to get a teaching degree.
“The kids adored her. Colleagues adored her,” Alford recalled, adding that her friend was “just very loving” and “very sweet.”
Denise — who had been adopted — had hoped to start a family of her own. But after two failed marriages, she decided to give another child the same opportunity she was given, and she adopted her son Carlos, then 4 years old, from Guatemala.
Who was Carlos Hallowell?
Friends of Denise said that Carlos was her “golden child,” with his charming personality, impressive athletic skills and academic talents. The mother and son eventually moved to their lake house in Inverness full-time.
“They bonded so well,” Alford, who had two adopted children of her own, recalled. “I even remember I was jealous because my girls and I struggled a lot and she and Carlos just hit it off perfectly.”
But the family dynamic would begin to shift after Denise adopted a second son, Angel Hallowell.
Who was Angel Hallowell?
Angel was 8 when Denise adopted him from Honduras. Denise had hoped that Angel and Carlos would bond as brothers, but friends said that Angel was “troubled” from the start.
The fraught relationship between Denise and Angel reached a crescendo in 2015 when she called 911 to report that Angel, then 12 years old, had run away from home. Angel was discovered hiding in a shed on Alford’s property.
But deputies from the Citrus County Sheriff’s Office were more concerned about what was going on at the Hallowell home, after finding that the boy’s windows had been nailed shut and that there was a lock installed on the outside of his door.
Angel later said that he was forced to urinate and defecate in a bucket, and was often locked in his sparse room. He also alleged that his mom had also been physical with him.
“She gets mad, and she slaps me, and all that stuff. I just, like, run away,” he told a social worker, as seen in video obtained by Dateline.
Denise Hallowell arrested after being accused of child abuse
Denise was arrested on allegations of child abuse and both boys were taken from her care. Local defense attorney Bill Grant soon took on the case and insisted that the allegations against her were false.
While Grant admitted that Denise had nailed down Angel’s windows and put a lock on his bedroom door, the attorney said it was because the boy had impossible fits of rage and was prone to running away. According to Grant, Denise often slept outside Angel’s door to make sure he was ok and only put the bucket in the room in the event of an emergency. Reports from Angel’s school and his foster family also demonstrated that he had angry outbursts.
Carlos came to his mom’s defense, insisting nothing abusive had been going on at the home.
“All accusations against mom are false except for, the ones that I know of, locking Angel in the room and that has a specific reason,” he told a social worker.
He denied that his mom was ever physically abusive and said it was Angel who’d “throw punches” or “try to scratch” people.
Denise was never formally charged in the case and she was reunited with Carlos several months later. But, according to Grant, professionals who evaluated Angel concluded it wouldn’t be healthy for him to return to Denise’s home and she agreed to give up her parental rights to the boy and he was placed in foster care.
The night Denise Hallowell died
With the allegations behind her, Denise was able to secure a new teaching job working with autistic kids and it seemed her life was once again back on track.
But in July of 2019, Denise was found dead in her bed with a large ax sticking out of her head. Deputies arrived to find the mom barely breathing, and resuscitation efforts were unsuccessful.
Carlos told investigators that he and his mom had gone to a funeral that morning, stopped off for pie on their way home and then each retired to their rooms at around 3 p.m. for their regular afternoon naps.
He said he watched some video clips on his phone before falling asleep, then woke up about two hours later after hearing the dogs barking outside. According to Carlos at the time, he got up to check on the dogs and discovered the front door of their home and the gate wide open. When he went into his mom’s room, he found her lying in bed with the fatal injury, he’d claimed.
“I don’t know anybody that would have done that,” he said at the time.
Police try to figure out who killed Denise Hallowell
Investigators launched a massive search effort by air and ground to try to find the unknown attacker, but eventually concluded that the killer was someone much closer to home. They considered the possibility that Angel had returned to seek his revenge, but the now 15-year-old was incarcerated at the time of the killing after committing an armed robbery.
Their focus shifted to Carlos, whose golden boy image had been shattered by then. Carlos started drinking at the age of 11 and was suspected of dealing drugs from the woods near his house. According to Alford, he’d also once wrecked his beloved pickup truck his mother bought him just to get back at her for something. Neighbors recall hearing loud screaming matches between the two.
At one point, after overdosing on pills, Carlos was committed to a secure mental health facility, where he was ultimately diagnosed with bipolar disorder and depression.
After searching the family’s home, detectives found manuals to security cameras among Denise’s things. While there were no cameras found in the home, there were cords where it looked like cameras had once been set up. Divers searched the nearby lake and found three security cameras and Denise’s missing phone not far off the shore.
“That was a huge, huge find for us,” Citrus County Sheriff’s Detective Rob Ramos told Dateline.
Denise and Carlos Hallowell’s phones contained important clues
Although authorities were not able to recover any images from the day of Denise’s murder from the waterlogged cameras, the discovery in the lake did give detectives more details about the timeline that day. According to data from Denise’s phone, it had been plugged in around 3:12 p.m. that afternoon, but was disconnected from its charging cord at around 3:45 p.m. Then the phone was seemingly tossed into the water at around 6:18 p.m.
The final clue came when the GPS tracking data on Carlos’ own phone clearly showed that he left his home and was walking down to the lake just as he was calling 911. Two months after the killing, Carlos was brought in for questioning and — after being confronted by all the data — admitted to getting the ax from the shed.
“I remember being outside at the shed, and grabbing the ax…,” he told detectives. “And that’s it. That’s all I remember.”
Carlos was arrested and taken to jail. A more muscular, tattooed Carlos went to trial two years later. He was convicted of first-degree murder and sentenced to life in prison, but because he was 17 years old at the time of the murder, his sentence will be evaluated again by a judge in 2044.
Where is Carlos Hallowell today?
Today, Carlos is serving out his sentence in the Holmes Correctional Institution in Florida, according to Florida Department of Corrections records.
In an interview with Dateline correspondent Dennis Murphy, Carlos said that although his relationship with Denise was once “great,” the family never recovered from the child abuse accusations and Angel’s departure.
“Things got a little bit more strict and — and a little bit distant,” he said. “You know, my mother and I, we were close, we were tight, and then we started falling off a little bit.”
According to Carlos, when Denise got angry with him, she allegedly would tell him things like, “I don’t love you,” and that she “should have never adopted” him as a boy, triggering deep seated abandonment issues within him.
“Her exact words were, ‘If I didn’t adopt you, you would still be on the streets,’” Carlos said.
What happened to Denise Hallowell?
Carlos said that on the last day of Denise’s life, the pair got into an argument about his college plans. While he wanted to go to a vocational school, she wanted him to go to a university. During their argument, Denise began to make the same kinds of comments, according to Carlos.
After they got home, Carlos went outside to do some yard work, but his mother’s comments kept replaying in his head, he said.
“I started thinking about, you know, everything my mom and I talked about in the car,” he told Dateline. “‘You’re not worth anything,’ ‘You’re a disappointment,’ you know, these words that she has told me over time that are all accumulating that are just kinda, kinda built up one day.”
Carlos said he took an ax inside and swung it at his sleeping mother.
“There really is no excuse for it,” he said. “There is no reason I should have done that.”
Carlos said he believes that he is rightfully in prison for the crime, but says he still yearns for his mom.
“I am very deeply and truly sorry for what I did. I did something very heinous and very unimaginable,” Carlos said. “I miss her. I love her and I wish I could take things back, but I can’t ‘cause I did that. I made that choice.”
