By 1963 , when Saloth Sar took over the Communist Party leadership , a number of leftists were beginning to escape Phnom Penh for the countryside ; Sen went underground .
Was to follow leftists in 1964 , hidden in the car boot of a Chinese diplomatic vehicle .
By 1963 , when Saloth Sar took over the Communist Party leadership , a number of leftists were beginning to escape Phnom Penh for the countryside ; Sen went underground and was to follow them in 1964 , hidden in the car boot of a Chinese diplomatic vehicle .