AMSTERDAM - Flags flew at half-mast on government buildings across the Netherlands on Tuesday, a day after a gunman opened fire on a tram on the outskirts of Utrecht, killing three people.
A suspect - 37-year-old Turkish-born Gokmen Tanis - was detained after a 7-hour manhunt on Monday, and by Dutch law must be brought before a judge by Thursday.
Authorities said they were still trying to establish the motive for the attack in the quiet residential neighborhood which also wounded five people.
Regional police commissioner Rob van Bree said on a late night talk show that there was no connection known yet between the suspect and the victims, while Prime Minister Mark Rutte said "terrorist" motives could still not be ruled out.
But in an evening press conference, Utrecht's top prosecutor, Rutger Jeuken, said family issues could also be involved.
The suspect had previously been arrested, Jeuken told reporters, without giving further details.
There was no immediate comment from Tanis or any lawyer representing him.
Dutch newspaper Algemeen Dagblad identified one of the victims as a 19-year-old woman who worked in a cafe and another as a local football coach who was the father of two young children. Both have Dutch surnames. The third victim has not been identified by police or press. Utrecht police did not answer telephone calls early on Tuesday but said in a Tweet they would issue a press statement "in the course of the morning."
Utrecht, the Netherlands' fourth largest city with a population of around 340,000, is known for its picturesque canals and large student population. Gun killings are rare there, as elsewhere in the Netherlands.