A 21-year-old woman injured three people at a school in Warsaw, marking the third attack at a school in Poland in less than a week. Police said the woman used a dangerous object to attack a 17-year-old. She later injured two more people, aged 17 and 24. Jakub Filipiak, a police spokesperson for Warsaw, said none of the victims’ injuries put their lives in danger. Authorities did not identify the educational institution, but said it was open on Saturday, 10 October. It was described as a higher education institution. Police said the attacker did not know any of the victims. The latest incident came after police carried out a nationwide crackdown following the two previous school attacks. Officers arrested dozens of people across Poland and checked about 50,000 schools. Earlier in the week, a 19-year-old student attacked classmates, teachers and passers-by at a vocational school in the Mazovia province, injuring nine before fleeing and being arrested nearby. The next day, a 15-year-old killed a caretaker and injured two other adults in a knife attack at his former primary school, also in Mazovia. In response to the attacks, schools across Poland increased security, and some suspended classes. Police conducted patrols around education sites, while authorities also pointed to concerns shared in online groups about possible further violence. Government officials said they found no evidence of an ongoing online challenge promoting school attacks, and they said there was no official confirmation that the incidents were linked. Latest: the 21-year-old attacker was arrested, and police investigations into the attacks are ongoing.