The man is identified in the Polish press by his first name and the initial of his surname: Michal O., born in 2002. He lived with his parents and his sister in Ostrowiec Swietokrzyski, a mid-sized town a two-hour drive from Krakow. The bugle call that on-duty firefighters sound every hour from the tower of St. Mary's Church, on Krakow's market square, has not been heard since Saturday evening. It is a first since 1939.
On Saturday, around 3 p.m. (2 p.m. GMT), an attacker appeared in a car near the square and opened fire at random. Passersby, tourists, taxi drivers and the coachmen of the city's emblematic horse-drawn carriages were in his path.
Fifteen people hospitalized with gunshot wounds saw their condition improve slightly overnight. Not all of them are yet out of danger, a police spokeswoman said, quoted by Polish media.
The killer is suspected of having caused a total of nine deaths, after his parents and his sister were found lying at their home with gunshot wounds.
Ten Poles are also injured, including two police officers.
Three bodies were found in an apartment in central Ostrowiec Swietokrzyski: a 53-year-old man and two women, aged 52 and 21.
Poles had not experienced such a massacre of civilians since the end of the communist regime (1944-1989).
He was armed with an AR-15-type semi-automatic rifle.
The Polish prosecutor's office announced the opening of a terrorism investigation. According to investigators quoted in the Polish press, Michal O. is at the center of the case.