My head is saying 'it was his mother, Anne did it'...however, where the actual fuck is Jenny Sumner? She was supposed to be his partner in the bedroom and the boardroom, yet since Frank was found dead, she has not been on screen for one second.
Why isn't she around? Is she not aware he is dead? Is she not coming to the factory to see Frank now that their deal is signed? What's going on?
I suspect Corrie boses are trying to let us forget who she is before revealing that is was infact HER whodunnit.