Two people were killed in a shooting during rush-hour traffic Thursday evening in Houston, police said. The suspect shot two men after getting into a crash on I-10, Houston Police Assistant Chief Bobby Dobbins said. Police said the shooter and another person inside his truck hit another car around 6 p.m., and fired rounds with a long rifle into the victims’ car, killing both men inside. A witness told USA Today that he fired his pistol at the suspect in self-defense, which caused the suspect to get back in his car and flee the scene of the crime. He is still at large, according to police. “One of the witnesses saw the weapon,” Dobbins said during a press conference. “He’s familiar with guns and he believes it was an AR-15.” The motive for the crime is still unclear, and Dobbins said it could range from road rage to narcotics.