Amanda was knocked unconscious on a hen's night. Now, she's bravely hunting the culprit.

It was a night out with girlfriends for a bachelorette party that turned horrific when Amanda Comparetto was knocked out by a man on the pavement.

Now, after the police struggled to make progress finding the culprit, 23-year-old Comparetto took it upon herself to find the man responsible on her own by sharing a post on Facebook that since went viral.

She said she and her friends were leaving a bar in Florida on February 20 when a man in a red shirt approached them aggressively.

“He grabbed one of the girls by her arms and said ‘this is my wife I am taking her with me’,” she posted to Facebook, Fox News reports.

“My friend just shoved him off of her and said, ‘What are you doing?’ and he was like, ‘This is my wife,’ he just kept saying that. And I was trying to talk to the guy, saying, ‘Leave us alone,’ and the next thing I knew he punched me and I woke up on the ground covered in my own blood.”

The post has since been taken down (after being shared more than 15,000 times, ABC News reports), but in it, Comparetto shared a video of the man and asked the public for help recognising him.

She and her girlfriends had taken the video while they were dancing earlier in the night. They'd given it to police, who had no luck identifying the man.

"If somebody knows something or who he is, if they could please come forward and tell us who he is. We don’t have to tell who you are, it will be confidential," Comparetto said.

"But we just want a name so we can bring him to justice so he doesn’t do this to someone else."

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