Who killed the second wife in silent witness?

Who killed the second wife in silent witness?
Arrr A really good twist in the tail
Whilst the husband was suspected he was only guilty of the first wife's murder.
The daughter had to take 3 months from her job as a nurse following a colleague being attacked by a patient. In the attack the colleague kept calling for help in Checkoslovakian - The girls mother was also Checkoslovakia and had called out the same words as she was murdered.
Having heard this again it triggered a recall in the daughter and she blamed the second wife for her mothers death as her father had been having an affair with the second wife and wanted wife number one out of the way. The daughter returned home and that night as her step mother (wife number 2) went to be the daughter hit her with a blue solid stone ashtray killing her.
The father got off with the offence and all seem settled. The father and daughter discussed the 2nd wife's death. The father went to the local police station and admitted not just to his first wife's murder but to protect his daughter admitted to the second as well. The programme moved to the autopsy room where both doctors where undertaking a autopsy - it was the daughter how had committed suicide by hanging herself. Queue titles - end.