A Minnesota woman has been accused in court of fatally shooting her boyfriend in what the authorities said was a prank that had gone horribly wrong.

Monalisa Perez, 19 shot at Pedro Ruiz as he held a book to his chest. He believed the book would stop the bullet.

The incident was recorded on video.

The couple's three-year-old child and nearly 30 onlookers watched as she fired the fatal bullet into his chest, news media reported.

Ruiz's aunt said they did it to increase their social media following.

Claudia Ruiz told WDAY-TV that her nephew had told her he wanted to do the stunt "because we want more viewers, we want to get famous".

"He had told me about that idea and I said, 'Don't do it. Don't do it. Why are you going to use a gun? Why?'" Claudia Ruiz told the news channel.

"They were in love, they loved each other," she said. "It was just a prank gone wrong."