Ion Rîmaru was born on October 12, 1946, in Corabia, Romania. He was the oldest of three boys in his family. His parents met and got married in Caracal. However, their marriage was troubled. They argued frequently, which created a tense environment at home. Eventually, his father, Florea, moved to Bucharest and began working as a night tram driver. Years later, it was revealed that Florea was involved in a series of murders himself, making the family background even more complex.

Ion did not perform well in school. He struggled with his studies and had to repeat the ninth grade. Even at a young age, he showed peculiar behavior. He created a scandal in his hometown when it was discovered he was in a sexual relationship with an underage girl who happened to be his teacher's daughter. When he turned 18, he was convicted of aggravated theft. Despite his issues, he received high marks for his conduct in school.

After high school, he attended the Faculty of Veterinary Medicine in 1966. He started with a low grade of 5.33 out of 10, and he repeated his second year. At the time of his arrest, he was attempting to pass his third year again. Some of his professors described him as shy and lacking in education. They noted that he had a very limited vocabulary and interests. His roommates reported that his behavior was strange, and they tended to keep their distance from him.

Rîmaru had a difficult time managing his anger. When he was upset, he sometimes harmed himself, resulting in numerous cuts on his arms and legs. In 1967, doctors diagnosed him with several health issues, including mental problems and a condition called esophageal spasm.

During his time at university, his unusual actions continued. One night, a classmate reported that he was prowling around the dormitory while others were sleeping.

In late 1970 and early 1971, Ion Rîmaru targeted restaurant waitresses in Bucharest. He attacked women who were alone and returning home after work. His assaults happened late at night during severe weather conditions like snowstorms and heavy rain. This made many women afraid to go out alone after dark. The police were slow to share information, which led to rumors and heightened fear in the community.

On March 4, 1971, a group of doctors diagnosed Rîmaru with suspected periodic epilepsy. This diagnosis would later connect him to one of his victims, Mihaela Ursu. When she was found murdered in May, a bloody medical note was discovered at the scene, along with strands of Rîmaru's hair.

Rîmaru's method of attacking shifted over time. He became less focused on waitresses and even targeted women who were together. On May 27, 1971, police took note of the suspicious behavior of several men and decided to investigate Rîmaru. They found him returning to his dormitory with an axe and a knife. Further evidence, including hair and bite marks, confirmed his guilt.

Rîmaru's known crimes include at least four murders, multiple attempted murders, and several rapes. After the murder of a waitress named Gheorghița Popa, police increased patrols in Bucharest, leading to many arrests. Despite this effort, Rîmaru committed more crimes before his capture.

His attacks were noted for their brutality. He would use various weapons, inflict severe injuries, and engage in acts like biting off flesh. He even continued to assault victims after death. Following his arrest, Rîmaru initially refused to cooperate but later confessed to several serious crimes during interrogations.

At his trial, Rîmaru attempted to claim insanity but eventually recanted his confessions. He was sentenced to death, a verdict that was met with applause in the courtroom. On October 23, 1971, he was executed by firing squad at Jilava Prison. In his final moments, he expressed anger and a desire to implicate his father in his actions. Rîmaru's grave remains unmarked.