ETA did not read posts prior to this one which i would remove but willjust leave it here till we know about the can.
Unsure offhand if the red shiny object was seen before or after the murder, but if it appeared afterward, i would wonder if SN was missing her knickers (Red/shiny?).
No mention of sex assault iirc, but there was a case of a woman who, according to the news, was sexually assaulted- no mention of what i came to learn was that she was tackled solely so the pervy perp could steal her worn underpants.
Other than that, the shiny red object as previously suggested could be a scarf wrapped around a hard object, if it was wrapped around a flashlight for example, it could provide muted light, serve as a weapon, and not look especially suspicious if you said you were looking for something in the dark.
Could be red bottom of screwdriver, fwiw, imo, speculation.
Sabina Nessa: Police hunt man 'carrying red object he may have been concealing' - LBC
Investigators have released CCTV images of a man they are hunting for (Picture: Metropolitan Police)