Leszek Jacek Pękalski was born on February 12, 1966, in Osieki, a small village in Poland.

Leszek Jacek Pękalski, known as The Vampire of Bytów, is a Polish murderer and suspected serial killer. He is believed to have killed at least 17 people between 1984 and 1992. At different points during the investigation and legal proceedings, Pękalski claimed to have murdered as many as 80 individuals, although he later withdrew those statements.

Pękalski was first arrested in 1992 for rape, for which he received a two-year suspended sentence. During the investigation, suspicions grew that he might be responsible for far more serious crimes. At various points in police custody, he confessed to as many as 80 murders, though he later retracted these admissions, claiming they had been exaggerated or misunderstood.

Investigators struggled with limited forensic evidence and inconsistent testimony. Ultimately, Pękalski was convicted in 1996 of a single murder, due to insufficient material proof in the other cases. Despite this, Polish police and prosecutors remained convinced he was responsible for at least 17 killings and potentially many more.

After serving time, he was set to be released in December 2017. Instead, he was transferred to the National Center for the Prevention of Dyssocial Behavior in Gostynin for evaluation. There, he was to be assessed by psychiatrists every six months. The court would then decide whether he should be detained further or released.