Six people were killed and 16 wounded when a gunman opened fire in the main square of Krakow on Saturday. Two surgeons who were having lunch nearby with their families gave first aid at the scene, Prof Michal Pedziwiatr said.
Pedziwiatr heads the department of general, oncological, metabolic and emergency surgery at the University Hospital in Krakow, the hospital said. He and Dr Mateusz Wierdak heard the shots as they ate in the city centre. Pedziwiatr's son ran up and said people were being shot and were falling.
Wierdak treated a police officer who had been hit in the chest in the gunfight. He packed dressings into the officer's chest and pushed his hands inside to stop the bleeding. Pedziwiatr said this undoubtedly saved the officer's life.
The surgeons helped both the police officers and the suspected attacker. "When you are saving a life, it does not matter who is who," Pedziwiatr said. When the shooting ended, he took over care of the other victims and the attacker.
The professor phoned John Paul II hospital, which has a department of thoracic and cardiac surgery, and insisted that the wounded officer be taken there. He said the hospital has specialists in such injuries and the officer's chances would be best there. Nobody knows how it would have ended without Wierdak's help, because the ambulance took a long time to arrive, Pedziwiatr added.
Six volunteers from the Dublin Civil Defence, who are trained to give medical help, also came to help. A member of the group said they were on a tourist trip and were close to the square during the shooting. The volunteers gave CPR and stopped heavy bleeding.
The dead are four women and two men. Four are Polish citizens and one is British. The sixth is not from Poland, and their nationality has not yet been announced.
Among the wounded are police officers Jakub Kulik and Artur Moranski. A spokesman for Lesser Poland province said both are stable after surgery. The attacker has had several operations and is in a "stable but very critical condition".
Police found three more bodies in the suspect's home: his parents and his sister.
The national prosecutor's office has opened an investigation, led by its unit for terrorist crimes. Prime minister Donald Tusk called the shooting an act of terrorism and promised that the motives would be examined carefully. He also warned of disinformation online.
"Until now, we have not had such drastic cases of terrorism in Poland," Tusk said.
Krakow is the second-largest city in Poland and lies in Lesser Poland province, in the south. In October, Poland saw a series of knife attacks in schools.
President Karol Nawrocki will declare national mourning on 8 and 9 November, his spokesman said.