As of April 2023[update], he was incarcerated in the California Health Care Facility;[2] in September 2024, he was extradited to Cook County, Illinois, to face trial for a 1993 murder.

He committed his first murder on August 13, 1993, when he stabbed his neighbor, 18-year-old Tricia Pacaccio, to death on her back doorstep.

Ellerin's injuries included a neck wound that nearly severed her head and deep punctures to the chest, stomach, and back.

[7] On December 1, 2005, Gargiulo stabbed his neighbor, 32-year-old Maria Bruno, to death at her home in El Monte, California.

On July 7, 2011, the Cook County State's Attorney charged Gargiulo with the first-degree murder of Tricia Pacaccio.

[3] Gargiulo allegedly told authorities in the Los Angeles County Jail that just because ten women were killed—and his DNA was present—does not mean he murdered anyone, leading investigators to believe that there are more victims.

[13] A pre-trial hearing was held on June 9, 2017, in Los Angeles Superior Court, with his trial scheduled to begin in October 2017.