Born in 1899 in the remote mountain village of Anogeio, in the region of Preveza, Greece, Thymios Retzos grew up under the shadow of hardship and violence. His older brother, Giannis, was three years his senior, and the two shared a close bond from an early age. In 1909, their father mysteriously disappeared. The truth remained buried until 1917, when Giannis, serving in the military at the time, discovered that their father's remains had been found in a remote pit—murdered and discarded.

His brother reached out to him, and together they hunted down the men responsible for their father's murder. After killing the perpetrators, the Retzos brothers retreated into the mountains and formed a band of outlaws. 

While Giannis was the clear leader, Thymios was no follower in the shadows. He participated in dozens of armed robberies, kidnappings, and cold-blooded murders. The gang, which operated across the Epirus region, made headlines and frightened entire communities. Their actions included the kidnapping and ransom of prominent locals and merchants, including the sons of business owners and individuals like Christos Papagiannopoulos, and Maramenos’ son, whose ransom reached 1,000,000 drachmas.

According to local authorities, and later reported by the Greek Gendarmerie, Thymios and the gang were responsible for up to 82 murders, far beyond what the public was initially aware of. These weren’t crimes of impulse. Their killings were strategic, cruel, and often involved betrayal from within. Informants, traitors, and even fellow gang members, like Stavros Sintoris and Kontogiorgis, were executed by the brothers to preserve their secrecy and dominance.

In 1924, a political wave of amnesty was granted to former outlaws in the region, and the Retzos brothers were among those who benefited. When Thymios and Giannis re-entered society, they were treated like returning heroes. Locals in Ioannina welcomed them with fanfare. The brothers even built connections with the upper class, police forces, and local officials. Officer Michalis Goudas later testified before Parliament that the Retzos were not just accepted but they were allegedly acting as "semi-official police agents," sharing intelligence and rubbing shoulders with the very authorities who once hunted them.

On June 13, 1926, Thymios took part in the gang’s most infamous act—the Petra Robbery, a violent ambush on a National Bank transport vehicle carrying 15 million drachmas. The robbers blocked the road with a fallen tree near Petra, then opened fire as the vehicle approached. The driver lost control and crashed, leading to the deaths of eight people.

The robbery turned into a national scandal. Investigations were chaotic and plagued by errors. Local officials clashed over responsibilities, and the government's handling of the case drew criticism in Parliament. Despite heavy manpower deployed, including military regiments and gendarmes, the brothers remained one step ahead.

Sensing imminent arrest, Thymios fled with Giannis. They crossed into Albania, paid bribes for false passports, and assumed new identities. Thymios became Nikolas Petre Dissos. From there, they slipped into Italy, boarded a train to Serbia, then escaped again to Romania, where they were briefly arrested but managed to escape. Their final hiding place was in Varna, Bulgaria, where they posed as grain traders and operated an import-export company.

In late 1928, their run ended. Through joint efforts between Greek and Bulgarian authorities, and key intelligence from Romanian Inspector Strati Stratilescu, the brothers were arrested and extradited to Greece in November 1928.

Their trial began in September 1929 at the Five-Member Court of Appeals in Corfu, alongside sixteen other accused. On October 7, Thymios and Giannis were sentenced to death by firing squad, along with three accomplices: Evangelos Kokalis, Konstantinos Kapsalis, and Filippas Diamantis.

The sentence was carried out on March 5, 1930. At 4 a.m., guards entered the prison. Fearing an escape attempt, the authorities kept the execution plans a secret until the final hour. The two brothers were transported in separate luxury vehicles, one of which was driven by a civilian who didn’t even know he was part of an execution escort.

The execution site was located outside the old fortress of Corfu, where dozens of junior police cadets were brought to witness the event. The brothers stood silently as the 30-man firing squad, including 15 gendarmes and 15 soldiers, took position. At 7 a.m., the command was given.

Thymios did not die instantly. While his brother Giannis collapsed immediately, Thymios was seen breathing after the smoke cleared. He suffered a prolonged, painful death before receiving a final, fatal shot. By 7:30 a.m., he was officially declared dead. His body, like the others, was taken to the cemetery where relatives awaited.