Eerily, at the Tesco checkout Jo is illuminated in the screen of a man who is also shopping nearby.
A reflection of guilt?
Was the man in the woolly hat next to Jo ever traced and eliminated from the investigation? He brushes past Jo, after previously taking a glance in her direction. If he has been traced and eliminated then these are the questions that I would have asked:
Isn't it likely that the person who killed Jo was
i. known to her.
ii. liked cider.
iii. liked vegetarian pizza
iv. was meeting her nearby, after pre-arrangement.
v. had a flat or vehicle in the vicinity (in which she was killed).
vi. was acquainted with the quarry.
vii. staged her abduction, after the murder, and 'dressed' her flat after dumping her body.
viii. lived in an area where a phone signal could not be obtained, or was distorted.
ix. was an old (secret) flame. Or....
x. secretely desired her over time at a 'close' distance .