One person was killed and at least four others were injured in a knife attack on the grounds of a Benedictine abbey in southern Poland on Thursday, news agency Reuters cited local media report.A 31-year-old Ukrainian citizen was detained following the attack at the Benedictine Abbey in Jaroslaw, police said in a statement.The motive behind the attack was not immediately known.The incident took place at a Benedictine Sisters monastery on the grounds of the abbey, according to local media reports.“We are aware that Father Stanisław has passed away and Father Marek is in serious condition; there are other casualties, but we do not have further details,” Sister Barbara Dendor told state broadcaster TVP Info.“When I arrived, there was total panic; young people who had come out of the center witnessed it — they were saying, ‘Some madman, some madman!'” she said.Police were at the scene and were investigating the circumstances surrounding the attack.