Dutch police said they were investigating a terror motive behind the Utrecht tram attack that killed three people on Monday.
Police found a letter in the suspect's car which indicated that the attacker may have had a terror motive. However, it is still unclear what prompted the suspect to open fire in the tram.
The suspect, Turkish-born Gokmen Tanis, opened fire inside a tram in Utrecht on Monday, killing three people and injuring several others. The city of Utrecht was under lockdown in the aftermath of the attack. Tanis was arrested after a seven-hour manhunt.
Police had released the picture of Tanis before making the arrest. Authorities lowered the threat level in the city from maximum level after his arrest.
The three Dutch victims were identified as a 19-year-old woman and two men aged 28 and 49. Police said that they are yet to establish a connection between Tanis and the three victims.
Dutch Prime Minister Mark Rutte held crisis talks soon after the incident. The incident comes only three days after white supremacists opened fire in two mosques in Christchurch, New Zealand, leaving 51 people dead and many other injured.