Sergei Ivanovich Dovzhenko was born on June 30, 1972, in Mariupol, Ukraine. He spent his early life in this city on the east coast, which is located in the Donetsk Oblast. Sergei pursued his education at the Mariupol Commercial College, where he studied to become a commodity researcher. His education would eventually lead him to different jobs in his later years.

After completing his studies, Sergei served in the army. During this time, he earned the nickname "Murchik." He was also involved in boxing and became a two-time vice-champion boxer in Ukraine. After his military service, Sergei worked as a private entrepreneur in the local market. Later, he was employed at a company in Mariupol called Citadel.

Following his job at Citadel, Sergei joined the police force. He attended a police school and underwent a ten-month internship in the militia. However, after his discharge from the police, he struggled to find work for a long time.

On June 18, 1997, the office of a company called Citadel was attacked. A security guard named Sergei Mitchenko was killed, and ₴5,000 went missing. Cartridges from a PM pistol were found at the scene, which led police to suspect Sergei Dovzhenko. He was arrested on June 27, 1997, but managed to prove his innocence after a lengthy investigation. However, he was dismissed from his job for forgery.

Feeling wronged by police and his former colleagues, Dovzhenko began plotting his revenge. His first known murder took place on November 19, 1998. He killed Vladimir Chekmak, the former owner of Citadel, and also attacked Chekmak’s friend, Igor Karimov. Dovzhenko continued to target those he felt had wronged him.

On April 17, 1999, he killed Valentina Gladilina, a businesswoman, after posing as a police officer. He used a special pistol, which he had purchased from a friend, for this murder. This same weapon was used in the later murders of militia captain Alexander Kokin and his wife, Ekaterina, on June 27, 1999.

Dovzhenko chose victims based on newspaper ads for valuable items. He believed that targeting these individuals would complicate police investigations and lead to their dismissal. In his spree, he killed Lyudmila Shevchenko and her son Sergei on September 10, 1999, and Ivan Vakulenko and his son Vitaly on December 13, 1999.

On July 7, 2000, Dovzhenko killed his friend Vitaly Shemyakov, who had begun blackmailing him after noticing the distinct weapon used in previous murders. Dovzhenko then shot and killed police officers Alexander Rogovets, Vladimir Fedorenko, and Andrei Karpenko on December 15, 2000, when they attempted to arrest him.

In a significant escalation, on June 27, 2001, he killed Claudia Bondarenko, the mother of his friend Shemyakov. He staged a robbery to cover his tracks, resulting in the deaths of neighbors Galina Ivanova and her granddaughter Tanya.

Dovzhenko's last known murders took place on May 17, 2002, when he killed Artur Frolkov and Atso Simovich, both of whom were selling a laptop.

He was arrested on the same day. In 2003, he confessed to 19 murders during his trial, which began on January 19, 2003. He was found guilty of 17 murders and sentenced to life in prison. His claims about the other murders, including those of Mitchenko, Chekmak, and Karimov, remain unsolved.