Juan Catalino Domínguez was born on May 4, 1910, in the small town of Rauch, Argentina. Very little is known about his early life. By 1933, Domínguez started committing thefts in the rural areas of Ayacucho and Coronel Vidal. From 1940 to 1943, he faced legal troubles and was incarcerated due to a fight that happened while he was working as a chauffeur in Mar del Plata.

By 1944, Domínguez was working as the caretaker for a luxurious house in the La Loma de Stella Maris neighborhood of Mar del Plata. He lived with his wife, Isabel Criado, who was 18 years old, and their young daughter, Marta. Despite facing financial difficulties, he invited a friend, Rafael Luchetti, to stay at their home. One day, Domínguez discovered Luchetti in a compromising situation with Isabel. In a fit of rage, Luchetti pulled out a gun and shot Domínguez in the leg as he tried to defend himself. After being shot, Luchetti took Isabel and Marta away in a car. Severely injured, Domínguez was soon found and taken to a hospital for treatment, where he recovered from his injuries.

After leaving the hospital, Juan Catalino Domínguez was determined to find Rafael Luchetti. He stalked Luchetti's mother’s house in Dolores, waiting for a chance to confront him. Catalino lived in a small shed and worked odd jobs. One night, he encountered his neighbors, Gregoria Rosas and Narciso Peñalba, and demanded to know Luchetti's whereabouts. When they couldn’t tell him, he violently attacked them with a knife, stabbing and kicking them until they were dead. He then dragged their bodies to a nearby haystack to hide them.

Once the murders were found, police launched a manhunt for Catalino. They tracked him to a hotel in Mendoza, where he was arrested without resistance. While being transported to La Plata, Catalino pretended to feel sick and convinced the guards to loosen his handcuffs. He slipped away into a cornfield, leaving his coat behind as a decoy. He was later recaptured after a brief escape but managed to break free again after asking a guard to remove his handcuffs in the hospital. He climbed out a bathroom window and stole a bicycle, riding off despite having a serious infection from his earlier injuries.

Catalino returned to Dolores, knowing Luchetti and his family were living there. When he was about to take action, Luchetti and Isabel fled, leaving their daughter Marta with him. During his time in hiding, Catalino worked different jobs and used fake names. On June 28, 1947, while loitering near a ranch in Azul, he killed ranch hand Braulio Leguizamón and hid his body in a pile of rags. Soon after, police discovered Marta's true identity and took her to an orphanage.

On July 8, 1947, Catalino murdered his employer, Guillermo Alberti, and another ranch hand, Victoriano Serrano, after they recognized him. He hid Alberti’s body under metal sheets and disposed of Serrano’s body by tying it to a horse. Catalino continued to search for his daughter in the area but eventually had to leave when authorities closed in.

Now under aliases like Pedro Montenegro, Catalino committed more robberies and thefts. On March 7, 1948, he returned to the Mehatz farm, where he shot Martín Mehatz and his sons, Martín Mayo and Marcelo. After killing them, he loaded their bodies into the family car and disposed of the car in the forest.

Afterward, while working on another farm, Juan Carlos Pétersen recognized him from news reports about the murders. Before the police could arrest him, Catalino fled again. On April 18, 1948, police received a tip about a robbery involving a sulky with red wheels. When the officers located the sulky, they found Catalino hiding. He opened fire on them, and the officers returned fire, killing him instantly. His partner in crime, Orlando Nelson Rosas, was caught shortly after but was released later. Catalino's daughter, Marta, remained in an institute until she was an adult.