AP Explains: Why ex-NFL star's murder conviction was erased

The ruling this week by a Massachusetts judge erasing the murder conviction of Aaron Hernandez, the former New England Patriots player who took his life in prison, has angered the victim's family and roiled prosecutors. It has also raised questions about how the legal principle on which the ruling was based is applied in Massachusetts and elsewhere. Hernandez was convicted of the 2013 killing of Odin Lloyd, a semi-professional football player.

Source: Yahoo.com