Leah was born January 1, 1929 in Moscow, Russia, to Rachel and Raphael Kosayov, some time after they had arrived there from Samarkand. Her father was a merchant and her mother a homemaker raising their four children. Leah was the youngest.

Raphael was known as a Zionist, and the authorities persecuted and arrested him numerous times. In 1934, when Leah was five, they fled, and after a year’s journey, including some time in Iraq, they arrived in the Land of Israel. They lived in South Tel Aviv. Raphael once again became a merchant, and the family maintained a conservative Religious Zionist home.

Leah studied in the girls’ school in Neve Zedek, attending high school at night. At age fourteen, she joined Brit Hashmona’im, based on a classmate’s recommendation. There she met Bezalel (Yossi), who would eventually become her husband. He influenced her ideological development and recruited her for Lehi.

At first, she posted posters and distributed materials. Her instructor was “Dov,” now Professor Yehezkel Stein, Israel Prize winner in medicine.

Her parents did not know about her activity in Lehi, and in order not to arouse suspicions, Dov thoughtfully made sure her missions would leave her time to get home. Still, she sometimes had to slip out at night; when the neighbors reported this to her mother Rachel, she responded stubbornly that this was slander.

Later on, her instructor was Nathan “Pinchas” Granewitz, with whom she had daily contact. Her job was to maintain contact with supporters to pvoide contributions, to hide fugitives, to treat the wounded, and more. She remained active until the movement disbanded.

In 1949, she married Bezalel, whom she had known well for seven years.

They have three sons and numerous grandchildren.