Arsenal defender Pablo Mari is being treated in hospital after he was stabbed in a supermarket near Milan on Thursday.
The 29-year-old, currently on a season-long loan at Serie A side Monza, is now recovering, but one of the five other victims died after an incident at a shopping centre in the town of Assago.
Italian police said one person had died, a 47-year-old Bolivian national who worked at the supermarket. Another employee was injured along with four customers, including Mari, whose agent said his injuries were not serious.
Monza Chief Executive Adriano Galliani told Sky Italy: "Pablo Mari had a fairly deep wound on his back, which fortunately did not touch his vital organs such as the lungs or others. His life is not in danger, he should recover quickly," .
The BBC said a 46-year-old suspect had been detained and that the motive for the attack was not clear.
In a statement issued shortly after their 2-0 Europa League defeat at PSV Eindhoven, Arsenal said everyone at the club was "shocked to hear the dreadful news about the stabbing in Italy, which has put a number of people in hospital including our on-loan centre-back Pablo Mari."
"Our thoughts are with Pablo and the other victims of this dreadful incident."
Arteta, in his post-match press conference added: "I just found out. I know (technical director) Edu has been in touch with his relatives. He’s in hospital but he seems to be okay."
