The murder of millionaire hairstylist Fabio Sementilli
Murder on TrialOn 23rd January 2017, emergency services descended on the usually quiet, upscale neighbourhood of Woodland Hills, California. The 49-year-old hair stylist and beauty executive Fabio Sementilli was found murdered at his million-dollar home, with multiple stab wounds to his neck, face and chest.
Friends and family were in utter disbelief. Fabio was a much-loved father, brother and husband who had no known enemies or criminal record. However, as investigators dug deeper, they exposed a shocking story of lust and betrayal.
Fabio’s case features on the new docuseries Murder on Trial, available now on Crime+Investigation, which takes you inside America’s most bloody homicide cases in raw, unfiltered detail.
The murder
In the early evening of 23rd January 2017, Fabio’s youngest daughter went outside onto the patio of the family’s Woodland Hills home. She couldn’t have anticipated the horror she would find.
Her father was lying unresponsive in a pool of blood, with multiple stab wounds to his head, chest and neck. He was so badly injured that she couldn't turn him over to start resuscitation. Panicked, she called 911. Emergency services arrived shortly, but Fabio was pronounced dead at the scene.
It didn’t take long for outpourings of grief. Fabio was a cherished member of his community and loved by everyone who met him. In an interview following his death, his sister, Mirella Sementilli, remembered her brother as a popular extrovert. 'He used to tell stories and he would engage people for hours,' she said. 'He’d always make everything really funny.'
Another person who was devastated by the murder was Fabio’s wife, Monica Sementilli. According to family friends, she was distraught when she arrived at the scene, rocking back and forth in the kitchen while chanting, 'I’m not a wife anymore.'
The investigation
At first, officers treated the murder as a burglary gone wrong. There had been an increase in home invasions in the affluent neighbourhood, causing fear among residents. Despite no signs of forced entry, Fabio’s Porsche was missing, which seemed to confirm their theory.
However, as time went on, they noticed several red flags. The stolen Porsche was later recovered several miles from the house and the property’s surveillance cameras were discovered to have been tampered with. And confusingly, there was no sign of a struggle inside the house.
Forensic experts also questioned the brutality of the murder. Usually, robberies are impersonal. Perpetrators are mostly concerned with entering and leaving a property as quickly as possible. In this instance, a defenceless Fabio had been stabbed in a frenzy, suggesting that the attack was targeted rather than opportunistic.
This prompted investigators to examine Fabio’s professional life and relationships.
A shocking affair
From the outside, Fabio had the picture-perfect life. He had plenty of friends and a family who loved him, including his wife, Monica, two daughters and a son from a previous relationship. But things are rarely as they seem, and suspicions soon fell on Monica, who was out of the house at the time.
It didn’t take long for investigators to establish that Monica had been having a long-term affair with Robert Louis Baker, her racquetball coach. Baker was already known to the police. In the early 1990s, he was charged with a sexual offence involving his teenage stepdaughter, who was a minor at the time. Unusually, he was also photographed at the memorial, despite having no personal relationship with Fabio.
Then, there was a forensic breakthrough. Baker’s blood was found inside the stolen Porsche, directly linking him to the crime. Further analysis of phone records revealed that he had been in frequent contact with Monica in the days and hours before the murder.
The two were arrested and charged with first-degree murder and conspiracy to commit murder.
Trial and aftermath
The trial was full of devastating twists and turns for the Sementilli family. Both Baker and Monica initially pleaded not guilty to the charges, despite mounting evidence against them.
However, as the pair awaited trial, Baker changed his plea to 'no contest'. This meant that Baker didn’t dispute the charges against him, effectively pleading guilty without formally admitting guilt. He was sentenced to life in prison without the possibility of parole.
He then said that Monica knew nothing about the murder. Prosecutors disagreed. They argued that she had shared the home’s security information with Baker and alerted him of Fabio’s whereabouts, effectively signing her husband’s death warrant.
In June 2025, several years after the crime, Monica was finally sentenced to life in prison without the possibility of parole. To this day, her daughters oppose the sentence and insist that their mother is innocent.
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