C.I.D. S01 E05 Kissa Raat Ke Shikar Ka: Part 1

A series of murders within a quick span of time shocks the entire neighbourhood. It all starts with the murder of a professor, dying because of a fatal blow to his head. A few days later, a woman on her way back from work is killed in a similar manner. What did the professor and this lady have in common that they had to die this way?