Erik Galen Menendez was born on November 27, 1970, in Blackwood, New Jersey, to José and Mary Louise "Kitty" Menendez. He was the younger brother of Lyle Menendez. The family later moved to Beverly Hills, California, where Erik attended high school and was known for his tennis skills.

Growing up, Erik and his brother Lyle were raised in a privileged environment, but they later alleged that their father was emotionally and sexually abusive, and that their mother was emotionally distant and negligent. These claims became central to their defense during their murder trials.

On August 20, 1989, Erik and Lyle Menendez murdered their parents, José and Kitty Menendez, in the den of their Beverly Hills mansion. Armed with 12-gauge shotguns, they shot their father multiple times, including a fatal shot to the back of the head, and their mother ten times, leaving her unrecognizable.

Following the murders, the brothers called 911, claiming to have discovered their parents' bodies. They initially told police that they believed the killings were related to organized crime. However, their lavish spending in the months following the murders raised suspicions.

In March 1990, Erik confessed to the murders during a session with his psychologist, Dr. Jerome Oziel. The confession was later reported to the police by Oziel's mistress, leading to the brothers' arrests.

Their first trials in 1993 ended in hung juries. In 1996, a retrial resulted in both brothers being convicted of first-degree murder and sentenced to life imprisonment without the possibility of parole.

In May 2025, a Los Angeles judge resentenced Erik and Lyle Menendez to 50 years to life, making them eligible for parole. The decision considered new evidence and the brothers' behavior during incarceration.