Scott Evans Dekraai was born on October 17, 1969. He worked as a tugboat operator and was involved in a serious accident in 2007 that resulted in significant leg injuries. Following the accident, he was diagnosed with post-traumatic stress disorder (PTSD). Dekraai divorced his wife, Michelle Fournier, in 2007 after four years of marriage. The couple had an eight-year-old son and were engaged in a contentious custody battle. Court documents indicated that Fournier feared Dekraai, describing him as unstable and abusive. In 2007, Dekraai's stepfather filed a restraining order against him, which expired before the shooting incident.

On October 12, 2011, at approximately 1:21 p.m., Scott Dekraai entered Salon Meritage in Seal Beach, California, where his ex-wife, Michelle Fournier, worked as a stylist. Wearing a bulletproof vest and armed with three firearms—a 9mm semi-automatic pistol, a .45-caliber semi-automatic pistol, and a .44 Magnum revolver—he opened fire inside the salon. Dekraai first shot and killed Fournier, then continued shooting, killing six others inside the salon. He then exited the salon and shot a man sitting in a parked car outside, bringing the total number of fatalities to eight. A ninth victim, Hattie Stretz, was critically injured but survived.

Dekraai was arrested shortly after the shooting, less than a mile from the crime scene. He pleaded guilty to eight counts of first-degree murder and one count of attempted murder on May 2, 2014. His sentencing was delayed due to a scandal involving the misuse of jailhouse informants by the Orange County Sheriff's Department, which led to the removal of the death penalty as a sentencing option. On September 22, 2017, Dekraai was sentenced to eight consecutive life terms without the possibility of parole and an additional term of seven years to life for attempted murder.