BOSTON (AP) — Former NFL star Aaron Hernandez is going on trial again for murder — this time for the 2012 fatal shootings of two men outside a Boston nightclub. Hernandez already is serving a life sentence for the 2013 killing of Odin Lloyd, a semi-professional football player who was dating the sister of Hernandez's fiancé.

A guide to the trial and key background about the case:

THE DEFENDANT

Hernandez, 27, was a star tight end for the New England Patriots. He grew up in Bristol, Connecticut, and played football at the University of Florida before being drafted by the Patriots in 2010. He played for the Patriots from 2010 to 2012. The team released him in June 2013, shortly after he was arrested in Lloyd's killing. In 2015, Hernandez was convicted of murder in Lloyd's death and is serving a life sentence without the possibility of parole.

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THE VICTIMS

Daniel de Abreu, 29, and Safiro Furtado, 28, were close friends who attended high school and served in the military together in Cape Verde before coming to the United States and settling in Boston. Family members and friends of the men have packed the courtroom for many of Hernandez's pretrial hearings.

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THE KILLINGS

The two men were fatally shot one night in July 2012 as they sat in a car at a red light after leaving a Boston nightclub. Prosecutors say Hernandez followed the men and fired five shots into their car after de Abreu accidentally bumped into Hernandez at the club and spilled some of his drink. At Hernandez's arraignment, prosecutor Patrick Haggan told a judge that in the months before the shooting, Hernandez had become increasingly convinced that people had been "testing, trying or otherwise disrespecting him when he frequented nightclubs in the area."

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THE TRIAL

Jury selection was scheduled to begin Monday in Suffolk Superior Court in Boston, but was postponed Sunday as a heavy overnight snowstorm approached. Prosecutors said jury selection would likely begin Tuesday, instead. Opening statements are slated for March 1. Prosecutors plan to call Alexander Bradley as their star witness. Bradley, a former friend of Hernandez, was with him in his car the night he allegedly shot de Abreu and Furtado. Prosecutors say Hernandez shot Bradley in the face in 2013 because he was worried Bradley might implicate him in the double slaying. Bradley survived, but lost his right eye. Hernandez is charged with witness intimidation in the Bradley shooting. Prosecutors have also said they plan to show jurors two Hernandez tattoos they say relate to the killings of de Abreu and Furtado.

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THE DEFENSE

Hernandez has pleaded not guilty and denied any role in the shootings of de Abreu and Furtado. His lawyers have not revealed their defense strategy in court, but they are expected to challenge Bradley's credibility. In a recent court filing, prosecutors asked the judge to prohibit Hernandez's lawyers from telling the jury about Bradley's criminal record. In a recent court filing, prosecutors said they anticipate that Hernandez's lawyers may try to argue that Bradley "had the propensity to commit the crimes" Hernandez is charged with. In January, Bradley was sentenced to five years in prison for shooting up a bar in Hartford, Connecticut, in 2014. No one was hurt.

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This story has been corrected to show jury selection is likely to begin Tuesday, not Thursday.