His parents and three brothers left for Israel in 1949, but he remained to finish a degree in electronics and to coordinate Jewish and Zionist activities. The government initiated an anti-Zionist campaign in 1951, after a military coup, and Cohen was arrested and interrogated over his Zionist activities. He took part in various Israeli covert operations in the country during the 1950s, although the Egyptian government could never prove his involvement in Operation Goshen, an Israeli operation to smuggle Egyptian Jews out of the country and resettle them in Israel due to increasing hostility in Egypt.