[s4e11] Judge, Jury And Executioner -

The investigation begins when collapses and dies during a mock trial competition. While the death initially appears to be from natural causes (convulsions), Maura Isles discovers a puncture wound indicating she was injected with Ritalin. Key elements related to this "piece" and the case include:

Aside from the murder case, this episode also features a subplot where discovers her mother, Angela , owes $27,000 in back taxes due to her father's negligence. [S4E11] Judge, Jury and Executioner

: Roger Thorson , the mock trial advisor and an old law school friend of the judge, was revealed as the murderer. He killed her to prevent her from exposing his involvement in the private prison scheme. The investigation begins when collapses and dies during

: A small amount of wet paint on the judge's hand leads detectives to a freshly painted railing in a stairwell, identifying the exact location where she was ambushed. : Roger Thorson , the mock trial advisor

: The judge had discovered that a private prison, to which she had been sending young offenders for rehabilitation, was actually a dangerous facility for "hard-core gangbangers".

"Rizzoli & Isles" Judge, Jury and Executioner (TV Episode 2013)