One prisoner held two others hostage for several hours at the penitentiary in Heerhugowaard, Noord-Holland, the DJI confirmed on Tuesday afternoon. The agency that runs the prisons said the motive was not immediately clear.There were no known injuries, a spokesperson for the DJI said. The hostages were released unharmed and the suspect was arrested at about 3 p.m.The hostages were being held in a common room, the DJI told both NH and ANP. The agency is responsible for the management of Dutch prisons and other facilities used to house people accused or convicted of a crime.