British police are still trying to determine the motive behind stabbings and a van hit-and-run in the central English city of Nottingham that left three dead and one seriously injured on Tuesday. The agents continued the questioning of the suspect, a 31-year-old man whose identity has not been revealed, but who the British media say is a person originally from West Africa, who has lived legally in the United Kingdom for many years, with history of mental health problems and no criminal record.

Police said they believe the attacker acted alone and was working with anti-terrorism officers to try to establish a motive. However, the attack has not been classified as terrorism by authorities, and police are investigating issues including the suspect’s mental health. Still, Nottinghamshire Police Chief Constable Kate Meynell was cautious in saying they were keeping an open mind. “We are still in the early stages of the investigation,” she said.

Two 19-year-olds, a man and a woman who were college students, were found dead on a downtown street with stab wounds around 4 a.m. Tuesday. Barnaby Webber and Grace Kumar, both cricketers and herself a hockey player, were returning from a party after finishing an exam.

Another 50-year-old man, identified as Ian Coates, who worked as a caretaker at a primary school, was also found dead with knife wounds on a road about two miles away.

Then a van, stolen from Coates, ran over three people, one of whom was seriously injured. After the vehicle came to a stop, police used a taser to arrest the man, whom they consider to be the only suspect.

The event took place for about 90 minutes in a large area of ??Nottingham, a university city of about 350,000 people about 175 kilometers north of London.

Webber’s parents and brother said he was “a beautiful, bright, brilliant young man with everything in life to look forward to,” according to a statement from the family, based in Taunton, in the southwest of the country. “The devastation complete is not sufficient to describe our grief and loss at the senseless murder of our son,” they added.

Kumar also played cricket and had played field hockey for the England youth teams. Woodford Wells Cricket Club, near London, noted that she was “a fiercely competitive, talented and dedicated cricketer and hockey player” who was “fun, friendly and brilliant”.

Coates’ employer mourned his loss, describing the man as a “dear and respected member” of the Huntington Academy.