The last suspect, Herman Cash, died in 1994 without being tried.
Across the country in recent months, several suspects who were shot with Tasers, sometimes repeatedly, have died.
Four suspects have died since original charges were filed.
A third man also considered a suspect in the case died of natural causes in 2008.
Where armed groups operate, it is common for the police or military to claim that political suspects have died in an 'encounter'.
Between 1990-2011 a total of 980 suspects died in police custody.
Another agent and two suspects died in the shooting.
Police initially believed the suspect may have died from his injuries shortly after the shooting.
The suspect who held the material directly in his hands died of radiation exposure 30 minutes later.
After three suspects die in a car accident, the case is closed.