Utrecht: Dutch authorities said on Tuesday they were “seriously” investigating a terrorist motive for the Utrecht tram attack because of evidence including a letter found in the suspected gunman’s getaway car.

Police were questioning Turkish-born main suspect Gokmen Tanis, 37, and two other men over Monday’s rampage in which three people were killed and seven injured, three seriously.

Dutch Prime Minister Mark Rutte had earlier said they “cannot exclude” other motives including a family dispute, but police and prosecutors said on Tuesday that the probe was leaning towards terrorism.

“So far, a terrorist motive is seriously being taken into account. This is based on a letter found in the getaway car among other things and the nature of the facts,” police and prosecutors said in a joint statement.

“Our investigation has established no link between the main suspect and the victims.”

The three people who died in the shooting were a 19-year-old woman from Vianen, south of Utrecht, and two men aged 28 and 49 from Utrecht itself, the statement said.

Armed police captured Tanis after an eight-hour manhunt that virtually shut down the Netherlands’ fourth largest city and triggered a nationwide increase in security at airports and key sites.

Police said they had found a red Renault Clio that the suspect had used as a getaway car after the attack. They had also found a firearm after his arrest, they added.

Tanis and two other men aged 23 and 27 are still being interrogated, police said.

A stream of mourners laid flowers on Tuesday at the site of the attack near the 24 Oktoberplein square.

“One of the victims was my friend’s girlfriend. So coming here today was the least I could do,” Marco van Rooijen, 43, said.

“I am here to pay homage to the victims and to support their families,” added local resident Yvette Koetjeloozekoot, 29. Flags were flying half-mast on many buildings around the Netherlands. Public transport was running again after forensic police finished their investigations at the scene and removed the tram on which the shooting erupted.

Rutte was chairing a cabinet meeting on the attack, which has raised security fears a day before provincial elections in the Netherlands.

Agence France-Presse