It happened around 2:30 p.m. Sunday at the Chop Shop hair salon at US 9 and Roberts Avenue in Marmora.
Fire officials say the blaze left multiple people trapped inside the building.
That's when, they say, a mystery man saw what was happening, grabbed a ladder and climbed to the second floor to rescue those trapped.
The business was destroyed.
There's still no word on what started the blaze.
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