RACINE, Wis. (CBS 58) -- The Wisconsin State Public Defender's Office is calling for an investigation of Racine County's juvenile detention center after a 15-year-old was allegedly assaulted by staff in May.

Surveillance and body camera footage from May 27 show security workers beating and restraining the teen at the Jonathan Delagrave Youth Development and Care Center, according to the State Public Defender's Office. Records obtained by the office indicate three of the four staff members involved remain employed at the center.

"I'm devastated. No mother should ever have to watch her child be beaten by the very people entrusted with his safety," said Kianna Reed, the child's mother. "Seeing that video and knowing my son is still in that facility is terrifying."

State Public Defender Jennifer Bias called for a full investigation into conditions at the facility. "The people in this video should have never been entrusted with caring for children," Bias said. "Instead of addressing its failure with transparency and accountability, Racine County has sought to sweep this incident under the rug."

The detention center opened May 1, according to the State Public Defender's Office. Records obtained by the office indicate one security worker resigned after the incident, and another was ordered to complete eight hours of training and remains employed.

The child's family is seeking an attorney for a civil lawsuit against Racine County, according to the office.