Police are confident that Aaron Hernandez had the means and opportunity to kill Odin Lloyd, and believe they have sufficient evidence of each.
Motive, however, has been a mystery throughout the investigation of the former NFL star, though a second case has given police a new angle.
Officials think Lloyd may have had information about Hernandez that the tight end felt would destroy his relationship with his fiancee and the Patriots.
There are several operating theories, but a prevailing one is that Lloyd "mouthed off" to Hernandez about "secrets" Aaron had told him in the past.
Those secrets, police believe, concern Aaron's involvement in drugs and his involvement in several violent incidents - possibly two other murders.