Margaret DeFrancisco was born along with her sister Regina in Chicago, Illinois. They grew up in the Pilsen neighborhood, an area known for its vibrant community and diverse cultural influences. Little is known about their early childhood or family background. However, it has been reported that the sisters had a close relationship during their teenage years.

As teenagers, both Margaret and Regina faced challenges typical of urban youth. They were part of a tight-knit circle of friends and engaged in typical adolescent activities. At some point, they became involved in a lifestyle that would eventually lead them to notoriety.

Margaret DeFrancisco was described as a rebellious young woman. She was known to have a strong personality, which sometimes caused conflicts with others around her. Regina and Margaret became inseparable, often making decisions together that would impact their lives significantly.

On June 6, 2000, Margaret DeFrancisco shot and killed 22-year-old Oscar Velazquez. This happened after Regina, Margaret's sister, called Velazquez over to their home. A friend of the sisters, Veronica Garcia, was also present. The friend had given Margaret a gun, believing it would be used for robbery. After shooting Velazquez in the back of the head, Margaret and Regina reportedly stole $600 from him. They then drove his body to a vacant lot, where Regina set it on fire using nail polish remover.

An anonymous caller alerted the police about the fire. When officers arrived, they found Velazquez's body being burned. The sisters attempted to sell Velazquez's car, a Camaro Z28, but when they could not find a buyer, they abandoned it and set it on fire as well. They were soon regarded as suspects in the murder due to conflicting stories when questioned by the police. Before they could be arrested, both sisters fled.

Nearly two years later, on March 24, 2002, Margaret was captured in Rockford, Illinois, after a tip was given following a broadcast of America's Most Wanted. She was charged with murder and unlawful flight to avoid prosecution. Regina was arrested later in Dallas, Texas, after a traffic stop and chase. She faced the same charges.

The trial for both Regina and Margaret began in July 2004. They pleaded not guilty, arguing self-defense. Veronica Garcia testified against them, claiming she did not know about the murder beforehand and had given the sisters the gun for robbery. Other prosecution witnesses also claimed both sisters confessed to the murder. Margaret testified that she shot Velazquez out of self-defense, claiming he was angry and threatened them. Regina claimed she heard a gunshot before seeing Margaret with the gun.

After a lengthy jury deliberation, Regina was found guilty of murder during an armed robbery. Margaret’s jury could not reach a unanimous decision, resulting in a mistrial. She was released on bail pending retrial. In November 2004, during her retrial, the same witnesses testified again. This time, Margaret was convicted of first-degree murder.

After the trials, Regina was sentenced to 35 years in prison, while Margaret received a 46-year sentence. Both sisters are serving their sentences at the Logan Correctional Center. They filed appeals that were unsuccessful. Meanwhile, Veronica Garcia was sentenced to five years for her involvement but was released after serving her time.