Is Witness Number 3 coming back?

Jodie is a single mum who runs a hairdressing salon. One day at work, Jodie momentarily glances out of the window and in a split second her life descends into freefall. 

What she notices seems innocuous – two men walking on the opposite side of the road – but she's actually witnessed a killer and his victim moments before he is murdered.

When the police make an appeal, Jodie does the right thing and comes forward, believing her information to be of little consequence. She's surprised when detectives decide to keep her identity secret, referring to her as ‘Witness No.3', and then it becomes clear why...