 Complete the following phrase:  At the end of July 1950 disciplinary brigades were established brigades 13 and 14, initially composed of former Pitești prisoners, headed by Iosif Steier and Coloman Fuchs. Violent reeducation was initiated there. Prisoners transferred form Pitești and Gherla, who were not considered fully reeducated, or canal workers who were actively opposing the camp regime, were transferred to these brigades, where they were tortured until they unmasked themselves. One of the most violent manifestation occurred on the night of 21 June 1951 later referred to  by prisoners  as 