A Minnesota woman has been charged with shooting dead her boyfriend in what she told police was a YouTube stunt gone wrong.

Monalisa Perez, 19, was charged on Wednesday with second-degree manslaughter in the death of Pedro Ruiz, 22, who she had been dating for five years. Perez told police Ruiz had planned the stunt, which involved her shooting him as he held a book to protect himself from the bullet.

The couple had recorded at least 18 YouTube videos together. The videos featured the young couple doing stunts, completing challenges and announcing the gender of their second child.

Before the shooting on Monday, Perez tweeted: “Me and Pedro are probably going to shoot one of the most dangerous videos ever. His idea, not mine.”

Monalisa Perez. Photograph: AP

Perez said Ruiz had shown her a book that had successfully stopped a bullet, according to the criminal complaint.

Perez told police she stood about a foot away from Ruiz, who was holding a hardcover encyclopedia in front of his chest, when she fired the gun. The incident was recorded on two cameras.

“I wish they wouldn’t have done it. I wish he would’ve just done another prank,” the victim’s aunt, Claudia Ruiz, told WDAY-TV.

Claudia Ruiz said the couple’s three-year-old daughter witnessed the shooting. “They were in love. It was just a prank gone wrong. It shouldn’t have happened like this. It shouldn’t have happened at all,” Ruiz said.

Perez is pregnant with the couple’s second child. She was released from jail on Wednesday afternoon after posting $7,000 bail.

Authorities found a Desert Eagle .50-caliber handgun in the grass near the home in Halstad, about 35 miles north of Fargo, North Dakota.

A YouTube video the couple recorded at a fair last week showcased their interest in recording YouTube videos. “Imagine when we have 300,000 subscribers,” Perez said in the video. Ruiz replied: “I told them, the bigger we get, I’ll be throwing parties.”