FILE PHOTO: People attend a silent march in Utrecht in honour of the people wounded or killed in an attack on a tram on Monday, in Utrecht, Netherlands March 22, 2019. REUTERS/Piroschka Van De Wouw/File Photo

AMSTERDAM (Reuters) - A 74-year-old man who was seriously wounded during a shooting on a tram in the Netherlands this month died of his injuries, taking the number of fatalities to four, Dutch prosecutors said on Thursday.

In a statement, prosecutors said they will adjust the charges against the alleged shooter, 37-year-old Turkish-born Gokmen Tanis, to four counts of murder or manslaughter, carried out with terrorist intent.

Authorities are investigating whether Gokmen, who is said to have confessed to a judge during a closed hearing, had other personal motives. He has also been undergoing a psychological evaluation.

In a rare act of gun violence in the Netherlands, Gokmen allegedly opened fire in a tram in the central Dutch city of Utrecht on March 18.

Those killed included a 19-year-old woman, a 28 year-old-man, and the 49-year-old father of two young children. One victim remains in hospital in critical condition.

A Dutch court will rule by the end of next week on extending Gokmen’s custody.