Haunting photos show Long Island teen Emily Finn happily dancing at prom with her ex-boyfriend who allegedly killed her in a botched murder-suicide before Thanksgiving.

Austin Lynch, 17, who awaits arraignment Friday in Suffolk County court, can be seen posing with and hoisting Finn, 18, in social media pics from the dance – months before their fateful breakup and the senseless shooting.

Another photo of Lynch unearthed by The Post chillingly shows him pose with a gun.

Long Island teen Emily Finn is seen in haunting photos happily dancing at prom with Austin Lynch, who allegedly killed her in a botched murder-suicide. emily_finn1015/Instagram

The pics were taken months before their breakup. emily_finn1015/Instagram

Lynch allegedly gunned down Finn inside his Nesconset home Wedne

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