A two-night special to be televised this Sunday and Monday will focus on 26 hours of never-before-aired phone conversations with mass killer Charles Manson, who died Nov. 19.

History announced plans today for “Manson Speaks: Inside the Mind of a Madman.” The program “will reveal new riveting evidence that suggests the Manson Family’s reign of terror may have extended beyond their notorious Los Angeles murders,” the announcement says.

“In addition to chronicling one of the most infamous crimes in U.S. history, the four-hour, two-night special investigates other mysterious deaths from the same timeframe and reveals new accounts of Manson’s violence and influence over others,” History says. “The special also examines 26 hours of exclusive never-before-broadcast phone conversations with Manson that may change the scope of his crimes, almost five decades later.”

Please click here to read the full announcement.