Five people including a police officer and a gunman have died in a shooting at a petrol station in the United States state of Missouri after the attacker went inside and opened fire, police said on Monday.Police said the man was also found dead, seemingly due to a self-inflicted gunshot. The dead included three citizens, Police Chief Paul Williams announced on Monday. A police officer was injured along with another citizen.Williams said police received reports of "multiple shooting calls throughout the city" late on Sunday. As officers responded, witnesses reported a vehicle crashed into a Kum & Go petrol station and convenience store, and the armed attacker ran inside and began shooting at customers and employees, Williams said.A person with a gun attacked a Missouri gas station, killing four people, including a police officer, Sunday night before ending it with a suicide, the authorities said.https://t.co/HzKRRE2iY8— erin mccann | (@mccanner) March 16, 2020Officers pulled the injured officers from the store and then went inside, where they found three citizens dead. The gunman was also found dead, apparently as a result of a self-inflicted gunshot, Williams said.Officer diesOfficer Christopher Walsh died at a hospital, Williams said. He was with the Springfield police for more than three years, was an Army veteran and was active in the Army reserves. Officer Josiah Overton, whose injuries are not life-threatening, has been with Springfield police for two years, he said."Both officers showed significant bravery and were heroic in their actions," Williams said.The identifies of the other victims have not been released pending notification of relatives.Police are still working to determine a motive for the shooting, the chief said.