Ibn Athir in Al-Kamil Fi Tarikh, Vol1, Pg591 says:
(Those who were tortured because of their conversion to Islam:) One of them was Laniba a slave-girl of
Bani Mo’ammal Ibn Habib Ibn Adi Ibn Ka’b. She converted to Islam before Umar, and he used to torture her
forcing her to apostate, in which he said to her: "I did not stop hitting you but for the fact I got tired." Whereupon she said: "Your God will do the same to you if you do not become Muslim!" Then Aboo Bakr
bought her and freed her. And another one of them who Umar used to torture was Zennaira from Bani Adi.
Alkarbala