A USB stick has revealed Mel McLaughlin was being stalked.

She’s walking through a shopping mall with a friend. Going to the movies with her husband’s children. Driving in traffic. Walking to her office.

Eighteen hours of footage stored on a USB stick shows an oblivious Melanie “Mel” McLaughlin going about her day-to-day life.

The device was left behind at a Sydney McDonald’s restaurant in March.

When the restaurant’s manager handed the drive to police, they stepped up their investigation into a series of threats McLaughlin had received to her work phone, as well as a recent break-in at her North Shore apartment.

It became clear: The 37-year-old sports television presenter was being stalked.

“Police have been involved in investigating a series of threats and serious incidents,” Jason Morrison, the news director of Seven Network Sydney and McLaughlin's boss, told The Daily Telegraph. 

“I am aware that police have spoken to a suspect several times and warned him. ­Despite that warning, the problem has continued.”

It's reported McLaughlin was the one to stop the police pressing charges against the suspect. It's also reported the stalker has threatened to "destroy" the Channel Seven employee if she files an apprehended violence order (AVO) against him.

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The footage is believed to have come from a private investigator, hired by the stalker to follow McLaughlin.

There are reports the man responsible is "obsessed" with McLaughlin and jealous of her partner, retired British footballer Ashley Westwood, 40.