Authorities are investigating the death of a 6-year-old boy who underwent treatment at Virginia Commonwealth University's dental clinic.

Crystal Lewis said her son, Jacobi Hill, went into cardiac arrest Tuesday after undergoing anesthesia while having caps put on several teeth. He was pronounced dead a short time later at VCU Medical Center. The state medical examiner's office is conducting an autopsy.

Lewis says Jacobi had asthma but no other known health problems. She says a pediatrician examined him Monday and concluded he was fine to have the dental procedure.

Lewis says a VCU School of Dentistry administrator informed her that officials didn't know what caused Jacobi's death.

A VCU spokeswoman declined to confirm the boy's death but said that an internal investigation is under way.