The stepmother of a 14-year-old accused of bullying a Florida girl before her suicide was arrested and charged with child abuse after a video depicting the woman beating a boy was posted on Facebook, a sheriff said Friday.

During a news conference, Polk County Sheriff Grady Judd said the arrest of 30-year-old Vivian Vosburg on two counts of child abuse with bodily harm and four counts of child neglect is a shocking chapter in a months-long tragic story in Central Florida.

Judd said Vosburg is the stepmother of one of two girls charged with felony aggravated stalking earlier in the week. Officials say the girls, 14 and 12, bullied and harassed 12-year-old Rebecca Sedwick before she climbed a tower at an abandoned concrete plant and hurled herself to her death Sept. 9.

It was a Facebook comment over the weekend that Judd said led him to arrest the girls.

He identified the girls and showed their mug shots during the news conference, but AP generally does not name juveniles charged with crimes.

Vosburg identified herself as the teen’s mother when she appeared on CNN and ABC to say the girl didn’t bully Rebecca and that she checked her stepdaughter’s Facebook every night.

Vosburg was booked into the Polk County Jail Friday evening.

Judd said that after detectives arrested Vosburg’s stepdaughter, people from the community saw her on TV — then sent tips to the law enforcement agency, urging them to look at the Facebook page of another of Vosburg’s children.

Detectives discovered a video posted in July 2013. According to the arrest affidavit, the video shows two boys fighting on a bed, then Vosberg steps in and begins punching and hitting the boys. One of the boys falls off the bed and appears to not move. Judd said none of the children were injured.

Child welfare authorities have been called to investigate.