A Kirkwood St. Louis-area man arrested by the FBI Thursday in Kirkwood was one of four Missouri men who paid a fifth to either watch him torture a mentally disabled woman online or torture her themselves, federal prosecutors said.

The 20-page indictment, unsealed with the men's arrests Thursday, contains horrific accusations of sexual and physical torture that lasted five years.

The alleged torturer, Edward Bagley Sr., 43, tattooed the woman to mark her as his slave, convinced her that she was legally "bound" to him and threatened her, including by claiming to have buried other bodies behind his trailer home and shooting animals that she cared for, prosecutors said.

Bagley tortured the woman for five years, until he induced a heart attack while suffocating and electrocuting her on Feb. 27, 2009, prosecutors said. She was taken to the hospital.

The alleged customers included Bradley Cook, 31, of Kirkwood, Dennis Henry, 50, the postmaster general of Nevada, Mo., and Michael Stokes, 62, of Lebanon, federal prosecutors said.