Milena Quaglini was born on March 25, 1957, in Mezzanino, Italy, near Broni in the Oltrepò Pavese region. She grew up in a small town and went to school there. After finishing her studies, she graduated as an accountant in Pavia. At the age of 19, Milena left her family home. She moved around, living in Como and Lodi, and worked various jobs. These included being a cashier, a caregiver, and a cleaning lady.

Milena got married and had a son. However, her husband became very ill with a severe form of diabetes. Sadly, he passed away, which deeply affected her. This loss led her into a long-term depression, and she began to drink alcohol to cope. Milena later moved to Travacò Siccomario, where she found a job in San Martino Siccomario. There, she met her second husband, Mario Fogli. Mario was an alcoholic who worked as a truck driver and had a difficult personality, often being jealous and closed off.

Milena and Mario had two daughters together. However, their life was filled with problems. When bailiffs showed up at their home due to Mario's debts, Milena decided to separate from him. She then moved to Este with her second daughter and took on a new job as a concierge for a gym. Milena struggled financially and took a job caring for an elderly man named Giusto Dalla Pozza. He lent her money but later tried to blackmail her. 

Her first victim was Giusto Dalla Pozza, an 83-year-old man she worked for as a caregiver. After he tried to blackmail her and attempted to rape her, a struggle occurred. Milena struck him on the head with a lamp, leaving him injured. He survived for ten days but ultimately died from his injuries.

After this incident, she returned to her husband, Mario Fogli. Following another argument on August 2, 1998, while under the influence of alcohol, she ended up killing him. She waited for him to sleep, then attacked him with a rope. During the struggle, Milena hit him with a jewelry box and eventually strangled him. She concealed his body in blankets and a carpet, leaving it on the balcony. Milena called the police, admitting to the murder.

Her third victim was Angelo Porrello, whom she killed on October 5, 1999. After he sexually assaulted her, she drugged his coffee with tranquilizers. When he fell asleep, she moved his body to the bathtub and filled it with water. Later, she placed his body in the garden. Milena was arrested after evidence linked her to the crime.

Milena Quaglini was sentenced to prison for these murders. While in custody, she struggled with depression. On October 16, 2001, she attempted to take her own life by hanging herself with a bed sheet. Despite being found alive initially, she died shortly after in the emergency room.