On a quiet morning in December 2023, the picturesque tourist peninsula of Búzios, Brazil, was shattered by a discovery that seemed more like a dark psychological thriller than reality. When local authorities arrived at a trail leading to the secluded José Gonçalves Beach, they encountered a scene of absolute tragedy.

Laying in the sand was 31-year-old Florencia Aranguren, an Argentinian artist whose life had been violently extinguished. There were no human witnesses, no security cameras monitoring the thick brush of the trail, and no obvious suspects. However, there was one presence that refused to be ignored: a dog named Tranco.

Tranco, whose name translates to “log” in Spanish—a nickname for a loyal friend—was Florencia’s constant companion. As the forensic teams moved in, the dog remained motionless beside her b0dy, his fur stained with bl00d and his breathing heavy with distress.

He growled at anyone who approached, protecting his owner even in her final, silent state. Little did the investigators know that this dog would eventually become the key to identifying a cold-bl00ded predator who thought he had committed the perfect crime.

To understand the weight of this tragedy, one must look at the vibrant life Florencia Aranguren lived before it was stolen. Born on November 20, 1993, in Buenos Aires, Florencia was a woman defined by her passion for the arts. She was a gifted illustrator and a dedicated aerial trapeze artist, often sharing her acrobatic performances and intricate tattoo designs on social media. Her life was a canvas of creativity, and Tranco was the anchor in her daily routine. Whether she was traveling across Europe or exploring the tropical landscapes of South America, Tranco was always by her side.

In 2023, seeking a deeper connection with nature and a more peaceful lifestyle, Florencia decided to move to Brazil. She was no stranger to the country, having visited Búzios previously with her friend, Macarena Sanchez.

She fell in love with the sun-drenched beaches and the slow pace of life, eventually deciding to make it her permanent home. For a few months, life seemed perfect. She spent her days exploring hiking trails and beaches with Tranco, documenting their adventures and planning a long-term future in the coastal paradise.

The events leading to the tragedy began on December 5, 2023, when Florencia took Tranco to a local veterinarian for a routine checkup. The vet requested she return the following morning for further tests. On December 6, at approximately 7:00 AM, Florencia left her home with Tranco.

Despite having a midday appointment, she decided to head out early to enjoy a walk on the José Gonçalves Beach trail. Security footage from a nearby road captured her final moments: a young woman in simple clothes, wearing a backpack, walking toward the trail with her dog trotting happily beside her.

Roughly an hour later, a local resident noticed a strange shape in the sand near the trail. Initially dismissing it as washed-up debris, the resident approached only to find Florencia’s b0dy covered in bl00d. The police were notified anonymously, and the investigation began immediately. As the forensic team processed the scene, they noted that Tranco refused to budge. He stayed by Florencia’s side, whimpering and guarding her until the authorities had to intervene.

While reviewing security footage from the surrounding area, investigators noticed a man on a bicycle wearing a hat, who had entered the trail approximately twenty minutes after Florencia. He was identified as Carlos Jose de Franca, a 32-year-old local who had been living in a nearby guest house for three months and worked selling goods to tourists on the beach. Initially, the police viewed him only as a potential witness who might have seen something.

The turning point occurred when the police brought Carlos Jose to the crime scene to see if he could provide any information. The moment Tranco saw him, the dog’s demeanor shifted from grief to pure aggression.

Tranco, who had been relatively calm with the officers, began barking and lunging at Carlos Jose with a ferocity that indicated recognition. He even attempted to bite the man, forcing officers to restrain him. To the experienced investigators, this was not random behavior; it was a positive identification by the victim’s closest companion.

Following the dog’s lead, the police shifted their focus. A background check on Carlos Jose revealed a horrifying criminal history. In 2009, he had been convicted of a br*tal robbery and the rape of a 15-year-old girl in the state of Pernambuco. He had served a portion of his fifteen-year sentence before being released on parole and moving to Búzios.

Armed with this information, police searched Carlos Jose’s residence. Inside a bucket of water, they found clothes he had been wearing that morning—the same clothes seen on the security footage.

They were soaked in a desperate attempt to wash away bl00dstains. Forensic analysis later confirmed that the bl00d on the clothes belonged to Florencia. Furthermore, DNA testing of skin samples found under Florencia’s fingernails—evidence of her brave struggle to defend herself—matched Carlos Jose’s genetic profile perfectly.

The autopsy revealed a br*tal end. Florencia had suffered multiple stab wounds to her neck, back, and chest. The cause of de@th was massive hemorrhaging. The marks on her hands told a story of a woman who fought with everything she had until her last breath.

The trial of Carlos Jose de Franca became a focal point for public anger in both Brazil and Argentina. It highlighted the dangers of parole systems that allow violent predators to relocate and reintegrate without proper oversight.

In April 2025, during a highly emotional jury trial, the prosecution presented a mountain of evidence, including the DNA matches, the bl00dy clothing, and the dramatic testimony regarding Tranco’s reaction. In an unprecedented move, Tranco was even brought into the courtroom, where his reaction to the defendant once again underscored the trauma of the event.

Carlos Jose was found guilty of first-degree m*rder and initially sentenced to 33 years in prison. He was also ordered to pay damages to Florencia’s family. However, the legal battle did not end there. In a move that has sparked renewed grief for the Aranguren family, an appeal by the defense led the State Court of Rio de Janeiro to reduce the sentence to 19 years and 2 months in a maximum-security facility, citing procedural irregularities.

Today, Florencia’s ashes rest in her hometown of Buenos Aires, brought back by a family devastated by loss. Tranco now lives with Florencia’s family in Argentina. Reports from the family describe a dog that still seems to be searching for his mistress, often restless and crying at the door.

He remains a living symbol of a bond that even de@th could not break—a silent hero who ensured that the man who took his “best friend” would not remain in the shadows. The case of Florencia Aranguren serves as a stark reminder of the importance of vigilance and the profound, almost supernatural loyalty of the animals we share our lives with.