The Lots

As the hope of the Jewish rebels dwindled that they would be able to withstand the Roman onslaught, Eleazar Ben Yair gave two speeches and convinced the leaders of this community of 960 in Masada that they would be better off taking their own lives than living in shame as Roman slaves. 

"Then, having chosen by lot ten of their number to dispatch the rest, they laid themselves down each beside his prostrate wife and children, and flinging their arms around them, offered their throats in readiness for the executants of the melancholy office.  These, having unswervingly slaughtered all, ordained the same rule of the lot for one another, that he on whom it fell should slay first the nine and then himself last of all...They had died in the belief that they had left not a soul of them alive to fall into Roman hands.  (Josephus Flavius, The War  of the Jews, VII)  

According to Josephus, 2 women and 5 children who had hid in the cisterns on the mountaintop told the Roman what had happened that night, the first day of Passover.