It's been over 40 years since the Jonestown massacre, yet there is still some mystery surrounding how the group's leader Jim Jones died. Was his gunshot self-inflicted? Could someone else have pulled the trigger through an act of heroism or loyalty? Is it possible he was already dying from other health problems?

One element of the 1978 mass death at Jonestown that hasn't been explored much is leader Jim Jones' rampant drug abuse—and how he used substances as a tool of control in his church. A&E True Crime investigate the roles drugs played at Jonestown.

A&E True Crime spoke with Marcus Parks—whose podcast "The Last Podcast on the Left" ran a special on Jonestown—to learn more about the last fateful hours of the men, women and children who died that tragic day.

Experts weigh in on whether the 918 people, including almost 300 children, who died during the Jonestown massacre were victims of suicide or murder.