Eight people were injured, four critically, afer a driver ploughed into pedestrians in the Italian city of Modena on Saturday.
Local authorities said that the driver tried to flee and was detained by police.
The man was known to officials for having mental disorders, they added.
He was identified as Salim El Koudri, a 31-year-old second-generation Italian who was born in Bergamo and now lives in the province of Modena.
El Koudri holds a degree in economics and is unemployed, authorities said.
He was detained and questioned at police headquarters in Modena as investigators tried to determine whether he acted deliberately.
There was no immediate indication that the man was under the influence of drugs or alcohol, investigators said at a press conference on Saturday evening. His home was searched as part of the police investigation.
Modena Prefect Fabrizia Triolo said that el Koudri had been known to local mental health services for schizoid disorders, while officials stressed that early findings pointed to possible mental instability but required further verification.
No links to extremist groups emerged.
Mayor Massimo Mezzetti said no one was killed in the dramatic crash, but four victims were in serious condition. He said a woman was pinned against a shop window and required the amputation of both legs.
Mr Mezzetti said the vehicle entered one of the city’s main streets and the man “drove onto the sidewalk, sending several people flying”, before crashing into the shop window.
Victims were taken to hospitals in Modena and Bologna, including by helicopter for the most critical cases.
El Koudri allegedly attempted to flee but was stopped first by some of the citizens involved in the crash and then by police and taken to headquarters for questioning.
Witnesses reported that the man was holding a knife, but he did not manage to stab anyone, the mayor said, adding that investigators are still working to determine whether the act was deliberate or linked to other causes.
“Whatever the nature, it is a very serious act,” Mr Mezzetti said.
“If it were an attack, it would be even more serious.”
Italian Premier Giorgia Meloni called the incident “extremely serious” in a social media post and expressed solidarity with the victims and their families.
Ms Meloni thanked those who intervened to help stop the suspect and praised law enforcement, adding she was in contact with local authorities and expected the suspect to be held fully accountable.
Emergency services, including police, carabinieri and financial police, responded to the scene, which was cordoned off as ambulances treated victims in the street.
