Attorney General William Barr released a statement following the news of convicted sex offender and accused sex-trafficker Jeffrey Epstein’s death, stating that he is “appalled” by the billionaire’s death in federal custody and adding that it “raises serious questions that must be answered.”

Authorities found Epstein dead in his jail cell early Saturday morning, with several reports calling it an apparent suicide. However, Barr said Epstein’s death raises “serious questions that must be answered.”

“I was appalled to learn that Jeffrey Epstein was found dead early this morning from an apparent suicide while in federal custody. Mr. Epstein’s death raises serious questions that must be answered,” Barr said in a statement.

“In addition to the FBI’s investigation, I have consulted with the Inspector General who is opening an investigation into the circumstances of Mr. Epstein’s death,” he added.

The FBI is reportedly investigating the circumstances surrounding the billionaire’s death, according to a U.S. Bureau of Prisons release Saturday:

Additionally, Rep. Al Green (D-TX) is calling for a congressional investigation:

The suicide of Mr. Epstein is an impossibilty. When an impossiblty occurs involving powerful people and possible criminality there must be an investigation to end speculation. Because the public has a right to know, I’m calling for a congressional investigation. #JefferyEpstein — Congressman Al Green (@RepAlGreen) August 10, 2019

Epstein’s death comes just weeks after prison officials found him semi-conscious in his jail cell with marks around his neck, suggesting a possible suicide attempt. While the accused sex-trafficker was thought to be on suicide watch, NBC reports that he “was not on suicide watch at the time of his death.”