MILAN >> A man grabbed a knife from a supermarket shelf Thursday and stabbed five people, killing one and wounding four others, including Spanish soccer player Pablo Mari, Italian authorities said.

Police arrested a 46-year-old Italian man suspected in the attack at a shopping center in Assago, a suburb of Milan, carabinieri said.

A supermarket employee died en route to the hospital, according to the news agency ANSA, which said three other victims were in serious condition. Another person was treated for shock but not hospitalized, police said.

The motive for the attacks was unknown, but police said the man showed signs of being psychologically unstable. There were no elements to suggest terrorism.

Mari, who is on loan to the Serie A club Monza from Arsenal, was among the wounded. Arsenal said in a statement that Mari was at the hospital but was not seriously hurt.

Monza club CEO Adrian Galliano wished the soccer player a speedy recovery in a message posted on Twitter.

“Dear Pablo, we are all close to your and to your family, we love you, continue to fight as you know how, you are a warrior and will heal quickly,″ Galliano said.

Witnesses told ANSA they saw people fleeing the supermarket in shock, and as the gravity of the situation became clear, shop workers pulled down the store’s shutters.

The Carrefour supermarket chain said that police and ambulance crews responded immediately to calls alerting them about the attack. The chain expressed its sympathies to employees and clients affected by the attack and said it was offering them psychological support.