Delaware prosecutors Monday mapped out their case against the first four inmates charged with the murder of Lt. Steven Floyd during a prison riot at James T. Vaughn Correctional Center last year, telling jurors that the attack unfolded in carefully planned phases.

In opening arguments, state Deputy Attorney General Nicole Warner described the “coordinated violence” of the 18-hour ordeal, and identified defendants Roman Shankaras and Dwayne Staats as having taken credit for masterminding a plot to overtake the prison’s C-Building on Feb. 1, 2017.