On a summer evening in Hatfield, Pennsylvania, a neighborhood barbeque turned into a scene of tragedy, leaving a young father dead. The man, Jeremy Chasteen, who was 31 years old, was attending a party with his wife, Felicia, and their six children on July 22, 2017. The gathering was hosted by Derrick and Whitney Cosby at their home on East Orvilla Road. As the night wore on, an argument erupted between Jeremy and Felicia Chasteen. The couple had reportedly been in their car preparing to leave when Felicia expressed concern that her husband was too intoxicated to drive.
The dispute escalated, and the couple went back inside the Cosby's residence. Inside the home, other partygoers intervened, attempting to separate the couple. It was during this chaotic moment that the homeowner, 43-year-old Derrick Cosby, became involved. According to Cosby's account to a 911 operator, he witnessed Jeremy Chasteen striking his wife. Believing he was protecting Felicia and others in his home, Cosby, a Navy veteran, retrieved his. 45-caliber handgun. Standing about five feet away, he fired a single shot, striking Jeremy Chasteen in the head.
Immediately after the shooting, at approximately 11:45 p.m., Derrick Cosby himself called 911 to report what had happened. He told the dispatcher that 'there was a domestic situation' and that he had shot a man who was 'beating his wife.' When police arrived, they found Jeremy Chasteen deceased in the family room. An autopsy later confirmed the cause of death was a gunshot wound to the head, and the manner of death was ruled a homicide. Although the shooter was immediately identified, the investigation continued. Felicia Chasteen initially stated that in the confusion, she did not see who shot her husband.
Following an investigation by the Montgomery County District Attorney's Office and Hatfield Township Police, Derrick Cosby was arrested and charged with voluntary manslaughter and possessing an instrument of crime. He was arraigned and released on bail. The case proceeded to trial, where the central issue became whether the shooting was a criminal act or a justified use of force under the law. Cosby's defense attorney argued that his client acted to protect people in his home from what he reasonably believed was the threat of imminent death or serious bodily injury, invoking Pennsylvania's 'Castle Doctrine' law. Prosecutors countered that the use of deadly force was unnecessary, arguing that Cosby could have called the police, who were stationed less than a mile away, and that he 'executed' Chasteen without warning.
In February 2019, after deliberating for about two and a half hours, a Montgomery County jury acquitted Derrick Cosby on all charges. The jury had specifically asked the judge to re-read the state's 'Castle Doctrine' law just before reaching their verdict. The acquittal brought an end to the legal proceedings, leaving the two families involved with the tragic outcome of that summer night.
