Create a free profile to get unlimited access to exclusive videos, breaking news, sweepstakes, and more!
The Allen family woke up the morning of July 7, 2019 to discover that Manuela “Manu” Allen, a beloved high school teacher and mother of four, had mysteriously vanished in the middle of the night.
The only clues left behind were a blood-soaked bedroom floor, bloody footprints, a knife, and blood smears throughout the family’s Olney, Texas home.
“There was blood splatter across the furniture, the mattress, the closet doors and as we proceeded into the garage we could clearly see drag marks,” Young County Sheriff’s Sgt. Dan Birbeck told “An Unexpected Killer,” airing Fridays at 8/7c on Oxygen, of the grisly scene left behind. “A picture started to develop that something very bad had happened.”
Manu’s husband, Peter, told investigators he had fallen asleep on the living room couch, adding he didn't hear anything suspicious all night.
But investigators were puzzled by how Peter — and two of the couple’s children who had been home that night — didn’t hear any evidence of a struggle, given the sheer volume of blood that had been left behind.
“Law enforcement believed there was a violent struggle in the bedroom. Mr. Allen was arguably within feet of the actual act occurring,” said Phillip Gregory, assistant district attorney for Stephens and Young Counties. “There were two children who were inside the house too and investigators were concerned that ‘Hey, how you not hear what was going on?’”
Peter said he and Manu had watched tv together the night before and then she went to bed in the couple’s bedroom, while Peter — who had been drinking vodka — slept on the couch.
His teenage daughter, Kiara, who slept in a room next door to her mother, reported coming home around 11:30 that night. She said she talked on the phone with a friend using earbuds and then fell asleep with the earbuds still in her ears.
The couple’s 20-year-old son Darian had also been home playing video games all night, but told authorities he had been wearing headphones.
“Darian said he had not heard anything other than he heard something in the middle of the night, but he just thought it was his father in the kitchen getting something,” said Dee Peavy, district attorney for Young and Stephens counties.
No one in the home noticed anything unusual until Kiara needed something from the laundry room — which was only accessible through her parent’s bedroom — the next morning and discovered blood in the hallway, before realizing the bedroom door was locked.
After finding the blood and the knife, Peter said he initially believed his wife had injured herself and drove to the hospital after he discovered her white SUV was also missing. Peter and his daughter drove to the local hospital to look for Manu before calling 911, a fact that struck investigators as odd.
“There seemed to be a lack of emotion. He was very calm,” Birbeck said.
Investigators believed that due to the amount of blood in the bedroom, Manu had likely either been killed or gravely injured and rushed to try to find the missing 49-year-old.
Archer County Sheriff’s Lt. David Wilk, who had known the family, volunteered to help in the search and headed to nearby Lake Cooper, a recreational area a few miles away. There, he discovered a white SUV abandoned after becoming stuck in the grass. When he got closer to the vehicle, he noticed brown smears that looked like blood.
Wilk scoured the area nearby and discovered Manu’s body wrapped in bloody blankets and sheets not far from a fence.
“I felt the body. It was cold to the touch, rigor had set in,” he told "An Unexpected Killer."
Investigators discovered that Manu had been stabbed approximately 47 times, strangled, and then shot once in the face post-mortem.
Birbeck described it as a “very brutal” homicide.
“It felt very personal. That started leading us to believe it was somebody who knew her,” he said.
The scene at the lake provided investigators with a few valuable clues: Bloody fingerprints had been left on the vehicle and authorities found bike tracks leading back toward Olney, suggesting the killer had possibly ridden a bike away from the scene. A witness also reported seeing someone riding a bike on the road in the early morning hours.
But who would have wanted the beloved teacher dead? Manu grew up in a village in southern Germany as one of nine children and came to the United States in college to study English. During her studies, she met Peter, a U.S. Army veteran, who was immediately smitten with the young college student.
They got married in 1996, settled in Texas, and soon started their family.
“My mom was a very supportive woman, but she was always pushing us to do our best,” said her daughter Melanie, who had been away on a trip to an amusement park the night of her mother's death.
The couple’s other son, William, 21, had been away at college at the time.
Peter insisted he couldn’t imagine who would want to harm his wife and suggested that someone may have been breaking into the home to steal some of his extensive gun collection.
Authorities were skeptical as nothing appeared to be missing from the home. Additionally, it seemed that the killer had gone into the kitchen and walked directly to an area where Manu’s car keys were typically stored, suggesting someone who was familiar with the teacher’s habits.
However, it was Peter’s suggestion that caused authorities to go and speak with a local teenager who was recently arrested for a burglary involving the theft of a firearm.
While investigators were talking to the teen, they noticed a bike at the apartment with tire tracks that looked very similar to the ones discovered at the lake near the body.
The teen told authorities that the bike belonged to his friend Julius Mullins, a teenage football player with a troubled home life who often found himself staying with friends or even crashing at the school gym.
Mullins had once dated Manu’s daughter Melanie, but the couple had broken up about six or seven months earlier.
While they were dating, Manu had been welcoming to Mullins and often helped him with his homework.
“My mom was extremely kind and accepting of Julius,” Melanie said.
But Melanie said she broke up with the teen after he started getting into more fights, struggling in school and arguing more often with her.
When investigators tracked the high school student down, they were disturbed to find that he had cuts along his arms and legs. Although he initially denied having any involvement in Manu’s death, he eventually admitted he had snuck into the home, killed her, and dragged the body out to the alley and loaded it into her car.
Mullins told investigators that he had killed her after meeting with Peter, who demanded he carry out the act — but there was no evidence to support his claims and authorities eventually concluded he had acted alone.
Mullins also admitted he was still in love with Melanie and was upset about the break up.
Her family believes heartbreak might have been the motive for the murder—although Mullins never provided any clear reason for his actions.
“The only thing I can think of he felt that if he killed Melanie’s mother that it would break her heart,” Peter said, calling it a “twisted revenge.”
Mullins pleaded guilty to murder in the first-degree and abuse of a corpse and was sentenced to 55 years behind bars.
In the years since her death, her family is still struggling to make sense of life without her.
“Manu was my life, she was my soul mate and I don’t think any human being alive could expect for their the heart, the core, the soul of the family to be murdered without reason whatsoever,” Peter said.
Crime News is your destination for true crime stories from around the world, breaking crime news, and information about Oxygen's original true crime shows and documentaries. Sign up for Oxygen Insider for all the best true crime content.