The Syrian man arrested in The Hague for stabbing three people on May 5 has been charged with three counts of attempted murder and a terrorist motive has not been ruled out, the public prosecution department said on Monday.

The investigation has turned up a Facebook message in which the 31-year-old stated that ‘unbelievers will suffer’ and the prosecution department admitted in late May that it had been tipped off about Malek F’s threats in March. Police are still trying to contact the tip giver.

F, who was shot by police during his arrest, is known to have a history of mentally disturbed behaviour and The Telegraaf reported that he had been involved in an incident in February where he threw furniture and possessions out of the window of his flat in the city centre.

Now the public prosecutor says the man should be sent to a secure psychiatric unit for observation, to assess the nature of his psychiatric issues. He has twice spend time in a psychiatric hospital in The Hague.

F is due to appear in court on Monday for a procedural hearing. The case will be heard at the high security courthouse at Schiphol airport, as is usual in cases where terrorism may be involved, the public prosecutor said.