BOSTON -- Former NFL star Aaron Hernandez killed two men in a hail of gunfire after he became enraged by “a simple bump, a spilled drink and an exchange of looks” in a Boston nightclub, a prosecutor said Wednesday in opening statements in the double-murder trial.

Hernandez’s lawyer, however, pinned the blamed for the killings on Alexander Bradley, former friend who was with Hernandez the night of the shootings and is expected to be the prosecution’s star witness. Hernandez has pleaded not guilty in the two murders.

Former New England Patriots tight end Aaron Hernandez looks toward the gallery of the courtroom as the judge recesses proceedings for the lunch break during the first day of his double murder trial at Suffolk Superior Court Wednesday, March 1, 2017 in Boston. His lawyer Jose Baez sits at right. Stephan Savoia, AP

Prosecutor Patrick Haggan told the jury that Hernandez had a brief encounter with Daniel de Abreu and Safiro Furtado at the club in the early morning hours of July 16, 2012. Two hours after de Abreu accidentally bumped into Hernandez and spilled his drink, Haggan said, Hernandez opened fire on the men’s car as they waited at a stoplight.

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Haggan said the encounter to most people would be “simply trivial,” but Hernandez misinterpreted it as a sign of disrespect.

Haggan said Hernandez “took the misperception to the ultimate level of violence – murder.”

Hernandez, a former New England Patriots tight end, is already is serving a life sentence after being convicted in the 2013 killing of Odin Lloyd, a semi-professional football player who was dating the sister of Hernandez’s fiancée.

Earlier Wednesday, a juror in Hernandez’s case was dismissed after a police officer scheduled to testify told the court they had once coached a football team together.

Hernandez’s lawyers were allowed to use a peremptory challenge to dismiss the juror. The case is now being heard by 15 people – 12 regular jurors and three alternates.

Hernandez, now 27, grew up in Connecticut and played for the Patriots from 2010 to 2012. The team released him in June 2013, shortly after he was arrested in Lloyd’s killing.

Prosecutors in the double murder case have said that in the months before the killings, Hernandez had become increasingly convinced that people had been “testing, trying or otherwise disrespecting him” when he went to area nightclubs.

On the night of the slayings, Haggan said that after de Abreu spilled the drink, he turned to smile at Hernandez – an act that enraged the football star.

“To Aaron Hernandez, that smile said it all – that was a sign of disrespect, and Aaron Hernandez was furious,” Haggan said.

Haggan said that after the encounter, Bradley was seen on video attempting to calm Hernandez down. The two decided to leave to go to another club, but Hernandez became convinced that de Abreu and Furtado were following him, Haggan said.

He said Bradley was driving Hernandez’s silver SUV when two hours later, they again encountered de Abreu and Furtado in a car with three other friends, stopped at a stoplight in Boston’s South End. He said Hernandez grabbed his revolver, aimed, and yelled “Yo” several times to get the men’s attention because he “wanted the victims in this case to see what was coming.”

“He said, ‘Yo, what’s up now?’ And a racial slur – the N word,” Haggan said. “He didn’t wait for a response – he fired the gun five times.”

Haggan said Furtado was struck twice in the head and died instantly. De Abreu, according to Haggan, was struck in the chest, dying several minutes later.

After the shooting, Hernandez and Bradley drove off, and Haggan said Hernandez attempted to conceal evidence and “cover his tracks.”

In the defense’s opening statement, however, Hernandez’ lawyer Jose Baez painted a starkly different picture of the events of the evening.

He called Bradley’s credibility into question and said his story amounted to “outright lies.” Baez questioned the motive prosecutors’ presented, arguing it was Bradley – whom he described as a dangerous drug trafficker known to be feared by his associates – who shot the two men over a drug deal.

Alexander Bradley in Hartford Superior Court in July 2013. CBS Boston

“Ladies and gentleman, this didn’t happen over a spilled drink – this happened over a drug deal,” Baez said. “Alexander Bradley had issues with Daniel de Abreu, and that’s why we’re all sitting here today.”

Baez blasted the police investigation, saying much of the evidence – including the victim’s bodies – were contaminated.

Baez said prosecutors want to convict Hernandez so badly they made “a deal with the devil.” Prosecutors have said Hernandez shot Bradley in the face in 2013 because he was worried Bradley might implicate him in the double murder. Bradley survived the shooting but lost his right eye.

De Abreu, 29, and 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. Haggan described them as hard-working immigrants who were only seeking to have a good time at the club the night they were killed.

The trial is expected to last four to six weeks.