Alfredo Galán Sotillo was born on April 5, 1978, in Puertollano, a city in the province of Ciudad Real, located in Castile-La Mancha, Spain. He grew up in a typical environment but was known to be introverted. In school, he became the class president, which showed he had some leadership abilities. However, many of his peers remembered him as unremarkable in terms of personality.

After finishing high school, Galán made a significant life choice. In September 1998, he joined the Spanish Army. He served as a corporal in the 31st Mech Regiment "Asturias," based in Madrid. During his time in the army, he participated in humanitarian missions in Bosnia, which was a challenging experience. After returning to Spain, he was involved in the clean-up efforts following the Prestige oil spill in 2002.

Despite his military service, Galán faced personal issues. He got in trouble when he stole a car, which led to his hospitalization at the Gómez Ulla Military Hospital in Madrid. There, he received a diagnosis of neurosis and anxiety. This diagnosis affected his life, and he began to drink alcohol more frequently.

In March 2003, he took a new job as a security guard at Madrid–Barajas Airport. This role came at a time when he was struggling with his mental health and personal problems.

On January 24, 2003, Alfredo Galán Sotillo committed his first murder. He shot Juan Francisco Ledesma in the head while Ledesma's 2-year-old son was present. This act was followed by the discovery of another body on February 5. The body of Juan Carlos Martín Estacio, a 28-year-old airport cleaner, was found shot in the head, along with an ace of cups card left nearby.

Later that same day, Galán went to Bar Rojas in Alcalá de Henares. There, he shot three people. The bar's owner, Teresa Sánchez García, survived despite being shot multiple times. However, her 18-year-old son Mikel Jiménez Sánchez and 57-year-old customer Juana Dolores Ucles López were killed. A two of cups card was left at the scene.

On March 7, 2003, Galán shot 27-year-old Santiago Eduardo Salas in the face. Salas managed to survive, and his friend Anahid Castillo Ruperti escaped unharmed. Another card, a two of cups, was found at this location.

On March 18, Galán killed a Romanian couple, Gheorgi Magda and his wife Diona, as they walked home from work in Arganda del Rey. At this scene, Galán left the three and four of cups cards. His choice to leave these cards was not planned. He began doing it after the media highlighted the earlier discovery of a card at a victim's crime scene.

On July 3, 2003, Galán went to a police station while drunk. He admitted to being "The Playing Card Killer." His confession revealed private details about the cards, which were not known to the public. After he sobered up, he recanted his confession. However, forensic evidence connected him to the murders through ballistic tests on spent cartridges found at his home. Reports indicated that he sometimes greeted his victims and ordered them to kneel before shooting them. He used a Tokarev 7.62-caliber TT-33 pistol, which he had brought back to Spain by hiding it in a television set.

Alfredo Galán was sentenced to 142 years and 3 months in prison. He is set to be released in 2028 after serving 25 years.