Ondrej Rigo was born on December 17, 1955, in Modra, Czechoslovakia. He was of Roma ethnicity and grew up in a challenging environment. His childhood was marked by significant events that shaped his early life. When Rigo was 14 years old, he and his siblings were taken away from their mother and placed in a youth corrective institution. Later, they moved to an orphanage. This change happened after their father was arrested. During this time, Rigo and his siblings lived in these institutions for about a year.

Rigo's family faced more tragedy when his mother died in 2000 after a car accident. Rigo stated that this was the only time he remembered crying in his life. His father also died during a burglary before Ondrej was an adult. Despite these hardships, Rigo claimed he had a good relationship with his parents, saying they did not beat him.

As an adult, Ondrej Rigo was a man of short stature. He had a daughter and was married twice. His first marriage occurred during his military service, which was mandatory in Czechoslovakia at the time. After his military service, his wife became jealous, leading to their separation. Little information is available about his second marriage, but it is noted that he was with a partner the night of his last murder.

In terms of work, Rigo had various jobs. He worked in the heater room of a hospital and was employed at Hotel Carlton in Bratislava, where he was later arrested. Before that, he worked as a fireman in a boiler room for the Pravda newspaper and in two hospitals, one on Bezručova Street and the other on Šulekova Street. He completed his gasman certification during his career.

Ondrej Rigo’s first murder took place in Munich on June 8, 1990. He entered the apartment of Helena S., who was 40 years old, through a partially open window. Rigo attacked her with a 2.5-kilogram metal pipe, striking her on the head and causing fatal injuries. After killing Helena S., Rigo covered her body with a blanket and sexually assaulted her corpse. He may have stolen some valuables before leaving, discarding the murder weapon beneath the bedroom window.

On August 1, 1990, Rigo struck again. He entered Ilka Z.’s apartment through a balcony door in Munich, killing her with the same metal pipe. He also stabbed her neck with a screwdriver during the attack. Afterward, he sexually assaulted her body and stole some of her possessions, including a golden necklace. The police later found evidence, including a sock and the murder weapon, at the crime scene.

Rigo moved to Amsterdam and killed his next victim, Maria van der W., on September 27, 1990. He accessed her ground-floor apartment through an open balcony window and used a heavy stone to bludgeon her to death. Afterward, he stripped her body, sexually assaulted her, and took various valuables before consuming a drink he found in the kitchen.\

On October 6, 1990, he returned to Slovakia and killed Terézia Reveszová, an 88-year-old woman, in a retirement home. He attacked her while she was sleeping, using his fists. After the murder, he stole several items from the retirement home.

Another brutal attack occurred on January 3, 1991, when Rigo entered a dormitory in Bratislava. He killed Anna Páleníková and her son, Juraj, by striking them both with a wooden stick while they slept. After the attack, he sexually assaulted Anna’s body.

On January 9, 1991, Rigo attempted to kill Jana B., but she fought back successfully, causing him to flee. This was the first time one of his intended victims survived. Despite the attack, the police failed to capture him immediately.

In April 1991, he murdered Helena Nováková, a 79-year-old woman, in her Bratislava home. He gained entry through a kitchen window and used a piece of concrete to kill her. Rigo's next victim, Henrieta Odlerová, was attacked on July 14, 1991. He entered her apartment through a window and inflicted life-threatening injuries. Henrieta initially survived for some days but ultimately succumbed to her injuries.

The last known murder Rigo committed was on March 4, 1992. He killed Matilda Urbanová, a 67-year-old woman, in a porch house in Bratislava. He left the scene to return home after spending time in a cinema with his girlfriend.

Rigo was arrested on March 4, 1992, shortly after Matilda's murder, in a hotel where he worked. Evidence and witness statements connected him to the crimes, confirming his identity and leading to a life imprisonment sentence for his actions. He never expressed remorse or admitted guilt during his trial.