Dowden’s (defendant) brother was arrested and held in the city jail at the police station. Dowden decided to help his brother escape and went with his sister-in-law and a friend, Clifford Blansett, to the police station with a rifle and a pistol. Upon entering, Dowden slammed open the door, pointed the automatic gun at two officers, and said he was there to get his brother. One of the officers, Captain Gray, lunged at Dowden, grabbing him and forcing him into the hallway. The door closed behind them. Officer Windham and a dispatcher, Denton, were in the office and could not see what was happening, but they heard a shot fired. Windham and Denton assumed Dowden had killed Captain Gray, because they could no longer see the officer. Windham and Denton then exchanged gunfire with Dowden. Windham heard movement in the hallway, and Denton yelled, “[h]e’s coming through the door.” After another gunshot, the door flung open, and Windham immediately shot three times while on his knees. Windham admitted that he did not look before he fired, because he thought it could only be Dowden coming through the door. It was soon discovered that the man lying in the doorway was not Dowden, but Captain Gray. Examination of the bullets indicated that Windham had killed Captain Gray. Dowden confessed to the events, stating that he opened the door to the office and started shooting after an officer lunged at him. Dowden was convicted of capital murder for the death of Captain Gray and sentenced to life in prison. Dowden appealed, arguing that the trial court erred in not granting his motion for a directed not-guilty verdict, because the evidence clearly showed that Officer Windham shot and killed Captain Gray. Dowden also complained that the court misinterpreted Texas’s penal code § 6.04(a), which states that a person is responsible if the result would not have occurred but for his conduct, either alone or together with another cause, unless the other cause was clearly sufficient to produce the result and the actor’s conduct clearly insufficient.