Adolf Gustav Seefeldt, born on March 6, 1870, in Potsdam, Germany, was the youngest of seven children. He trained as a locksmith and later as a watchmaker, earning nicknames such as "Uncle Tick Tock" and "Uncle Adi" due to his profession. In 1890, he married Katarina Seefeldt; the couple divorced in 1910. Their son was later institutionalized for moral crimes at the age of nineteen.

At the age of 12, Seefeldt reportedly suffered abuse by two men, an event that may have influenced his later actions. By 25, he faced his first imprisonment for sexually harassing a boy. Psychiatrists diagnosed him as mentally unstable, leading to extended periods in mental hospitals and prisons.

Between 1933 and 1935, Seefeldt traveled as a watchmaker, targeting boys aged between 4 and 11. He lured them into pine forests, where he abused and subsequently killed them. Notably, all his victims were found wearing sailor suits, lying peacefully without visible signs of violence, which perplexed authorities regarding the cause of death. ​

Contemporary experts speculated that Seefeldt used homemade poisons or chloroform to subdue his victims. However, some theories suggest he may have hypnotized them, performed sexual acts, and left them to die from exposure, failing to awaken them from hypnosis.

Seefeldt was apprehended in 1935 and stood trial in Schwerin. The proceedings began on January 21, 1936, with the court delivering a guilty verdict for twelve counts of murder on February 22, 1936. He was sentenced to death. ​On May 23, 1936, Adolf Gustav Seefeldt was executed by guillotine in Schwerin.