The Pompe secure psychiatric clinic in Nijmegen has launched an internal investigation after three prisoners escaped and one committed suicide while out on leave, broadcaster NOS said on Friday.

Two of the three men who escaped were recaptured quickly but the third, who made off on a bike, was found in Paris five days after he vanished. On Thursday another man committed suicide by driving into a lorry while on leave.

Lawyers specialising in psychiatric prison cases say the escapes have been motivated by frustration because of the shortage of staff.

‘Things are escalating over a short period,’ lawyer Jan-Jesse Lieftink told broadcaster NOS. He describes the Pompe clinic as possibly the best in the Netherlands.

‘This can happen anywhere and it does happen everywhere,’ he said. ‘What is reported in the media is the tip of the iceberg. But you must realise that official leave for people sentenced to psychiatric prison terms is extremely important and part of the system.’

The man who made it to Paris said in emails to local broadcaster Omroep Gelderland that the personnel are ‘a joke’. ‘Schoolgirls of 20 to 22 are supposed to tell me how to live my life?’ The shortage of staff was one of the reasons he took off, he told the broadcaster.

In a statement about the Paris escape, the clinic said: ‘We are doing all we can to prevent incidents, but they cannot be ruled out entirely.’