PROVIDENCE, R.I. — Investigators looking into why eight circus acrobats plummeted to the ground during an aerial hair-hanging stunt have found that a clamp snapped, a public safety official said Monday.

“We have identified a clamp that snapped that held them to the rafters, and it failed,” Providence Public Safety Commissioner Steven Pare told WPRO-AM a day after a support frame collapsed during the Ringling Bros. and Barnum and Bailey circus.

Three of the acrobats remained in critical condition Monday morning. Several performers on the ground also were injured. None of the injuries appear to be life-threatening, said Stephen Payne, a spokesman for Feld Entertainment, the parent company of Ringling Bros.

“They’ve used this act many times,” Pare told WPRO. “Unfortunately this particular clamp failed. It snapped off. We have it, we’re analyzing it, we’re seeing why it happened to ensure it doesn’t happen in the future. That’s all part of our focus.”

Investigators from the federal Occupational Safety and Health Administration are probing Sunday’s accident, along with local authorities.

The act is part of the “Legends” show, during which performers hang “like a human chandelier” using their hair. Eight of the injured were members of the same circus troupe, and are from the United States, Brazil, Bulgaria and Ukraine, according to the circus’s website.

A spokeswoman for Rhode Island Hospital said performers Dayana Costa, Julissa Segrera and Stefany Neves were in critical condition.