Love story turns violent in shocking gun violence PSA

Love story turns violent in shocking gun violence PSA

A high school romance provides a sufficiently distracting backdrop for a spine-chilling public service announcement urging people to be attentive to signs of gun violence in the US.

The advertisement draws you into the story of Evan, a student who we first meet while he's studying in the library.

Out of boredom, he writes on the desk - and when he returns to study at the same spot the following day, a girl has responded by writing back.

Evan is drawn in instantly by this mystery girl, and the pair continue their conversation via the desk as he frantically attempts to work out who she is.

Finally, while signing a friend's yearbook, the girl recognises his handwriting and they realise who each other are.

They share a brief conversation before all hell breaks loose; another student enters the hall they're in and cocks an assault rifle, which sparks screaming and running en masse.

Then, an ominous message: "While you were watching Evan, another student was showing signs of planning a shooting. But no one noticed."

"Gun violence is preventable when you know the signs," the video says.

It then rewinds to a number of key moments involving the shooter, who exhibits a range of troubling behaviours throughout the video that the viewer is unlikely to have noticed.

The shooter is seen posing with a gun on social media, watching a sniper on a YouTube video, reading a book about guns, doing the finger to another person in the library, getting bullied in the hallway, and pretending to shoot a teacher.

The video is produced by Sandy Hook Promise, an organisation that "educates and empowers parents, schools and community organisations on how to prevent gun violence before it happens".

It was founded in the wake of the catastrophic shooting at Sandy Hook Elementary School that resulted in the deaths of 26 people in December 2012.