Pol Pot had grown suspicious of Son Sen and in June 1997 ordered his death. Khmer Rouge cadres subsequently killed Sen and 13 of his family members and aides; Pol Pot later stated that he had not sanctioned all of these killings. Ta Mok was concerned that Pol Pot could turn on him too. Mok rallied troops loyal to him at Anlong Veng, informing them that Pol Pot had betrayed their movement and then headed to Kbal Ansoang. Fearing Mok's troops, on 12 June Pol Pot, his family, and several bodyguards fled on foot. Pol Pot was very frail and had to be carried. After Mok's troops apprehended them, Pol Pot was placed under house arrest. Khieu Samphân and Nuon Chea sided with Mok.