Translation of "delve into" into Arabic

However, when some later theologians delved into the ransom doctrine, they came up with some difficult questions, such as, To whom was the ransom paid?

إلا انه عندما بحث بعض اللاهوتيين الاحدث في عقيدة الفدية، خرجوا ببعض الاسئلة الصعبة، مثل، الى مَن دُفعت الفدية؟