David Ray Conley III was born on December 29, 1966. He grew up in Texas. Not much information is available about his early childhood or the specific details of his family life.

As he became an adult, Conley faced various troubles with the law. His criminal history began in 1988 when he was first arrested. Over the years, he accumulated many charges. These included domestic violence, driving under the influence (DUI), and drug possession.

Conley was known to have a history of being violent. In 2000 and 2013, he was arrested for being abusive towards his former girlfriend, Valerie Jackson. He struggled with issues related to anger and jealousy. According to reports from her brother, he was also said to have bipolar disorder, which affected his behavior.

At the time of certain incidents, he was married to Vernessa Conley but the couple was estranged. Reports suggest that he was abusive towards her as well. There were claims that he sometimes pretended to have mental illnesses to avoid facing legal consequences for his actions.

On August 8, 2015, David Ray Conley III broke into a house in Harris County, Texas, at around 10:30 a.m. This house belonged to his former girlfriend, Valerie Jackson. After finding that Valerie had changed the locks, he entered through an unlocked window. Conley confronted Valerie, her husband Dwayne, and their six children, forcing them into the master bedroom. He restrained some family members with ropes and handcuffs.

Over the next nine hours, Conley used a 9mm handgun to shoot Valerie's husband and children in the back of the head, while Valerie was forced to watch. She was the last person he shot. During this time, Valerie managed to text her mother, informing her that she was being held at gunpoint.

Throughout the ordeal, police officers were sent to the house multiple times after receiving welfare check requests. They were first notified by Valerie's mother at 10:42 a.m. Each time they checked, they received no response. The police returned several times in the afternoon but found no signs of life or a way to enter the home without a warrant.

Around 6:00 p.m., officers learned that a suspect inside the house had an outstanding warrant. They began to circle the home and spotted a body through a window. At around 8:00 p.m., police entered the house. Conley then began firing at them, which caused the officers to retreat. He surrendered an hour later.

In total, Conley fired at least 34 rounds during the shooting. All eight victims, including six children and two adults, died at the scene from gunshot wounds. After the incident, Conley confessed to Valerie's brother that he had killed the family but later recanted this confession during a jailhouse interview. He claimed he was "fed up" with how they were raising the children and felt disrespected by them.

Conley was charged with three counts of capital murder and held without bond. After legal proceedings, he was convicted in October 2021 and sentenced to life in prison without parole. The prosecution had initially considered seeking the death penalty but later dropped that pursuit, citing Conley's mental disability. As of January 2025, he is incarcerated at the W.J. Estelle Unit in Huntsville, Texas.