Fyodor Nikolayevich Kozlov was born on April 9, 1959, in the village of Semiyarsk, located in the Semipalatinsk Oblast of the Kazakh SSR. Shortly after his birth, his family moved to Rostov Oblast in the RSFSR, where he spent most of his childhood. Growing up, Fyodor was an introverted child. He struggled to make friends and was often seen as a social outcast by his classmates. This isolation led him to lose interest in school around the mid-1970s, which created tension between him and his parents.

As a teenager, Fyodor began to show aggressive behavior and possible signs of mental health issues. In early 1976, when he was 17 years old, he was sent to live with his grandmother in an attempt to improve his situation. However, this change did not help his mental state. It was during this period that he committed a serious crime. During a mental break, he assaulted his 11-year-old third cousin. His grandmother tried to intervene, but in a fit of rage, Fyodor killed both her and the child with an axe.

Following these tragic events, Fyodor was quickly arrested. Because he was still a minor, he received a sentence of 10 years in prison, which was the maximum penalty for someone his age. He served his time and was released in 1986. After his release, he moved to Novosibirsk Oblast. There, he married a woman he had written to while incarcerated, and they had a child together. However, his wife soon moved back in with her parents, leaving Fyodor alone in Lozhok.

In June 1989, Fyodor Kozlov committed his first murder shortly after being released from prison. On June 16, he approached an 18-year-old woman named Natalya Rodnikova near a train station. He used a knife to threaten her, dragged her into the woods, and killed her. That same night, he returned to the scene, covered her body with branches, and set it on fire to destroy evidence. The next day, her father found her charred remains.

In early July, Kozlov attacked a 12-year-old girl named Masha Dorofeeva in Iskitim. After luring her to an abandoned building, he tied her up and assaulted her before killing her and burning her body. A few days later, he attempted to abduct another young woman, but she escaped and reported the attack to the police.

To mislead the investigation, Kozlov moved to Novosibirsk in early August. He killed an 18-year-old girl he encountered on the street, burned her body, and repeated this method with a 24-year-old woman a few days later. This prompted police to increase their efforts to catch him.

On August 21, while visiting Omsk, Kozlov attacked an 11-year-old girl in a similar manner. The pattern in his murders connected back to the earlier cases, leading investigators to realize that they were looking for the same perpetrator.

Kozlov returned to Novosibirsk and attempted another attack on September 1. However, his victim fought back and attracted attention, causing him to flee. After her detailed description of him, police arrested Kozlov later that day at a bus station. During the search, they found incriminating items, including a knife and a white ribbon.

Once in custody, Kozlov confessed to five murders and five attempted murders. He was tried and found guilty on April 23, 1990. The court sentenced him to death, but while awaiting execution in prison, he hanged himself on September 1, 1990.