BOSTON (AP) — A spilled drink prompted former New England Patriots tight end Aaron Hernandez to stalk the stranger who had accidentally bumped into him at a Boston nightclub then open fire on his car, killing him and a second man, prosecutors said Wednesday.

"I think I got one in the head and one in the chest," Hernandez said to a friend as they fled the scene in an SUV, prosecutors told the court at the former star's arraignment.

Hernandez, already charged with killing another man last year, pleaded not guilty Wednesday to seven charges — including two counts of first-degree murder — in the 2012 shooting that killed Daniel de Abreu and Safiro Furtado. A third man was wounded.

In the months before the killings, Suffolk County First Assistant District Attorney Patrick Haggan said Hernandez had become increasingly convinced that people "had been testing, trying or otherwise disrespecting him when he frequented nightclubs in the area."

The night de Abreu and Furtado were killed, Haggan said Hernandez and a friend drove from Connecticut to Boston to go to a nightclub called Cure. They were standing at the edge of the dance floor when de Abreu accidentally bumped into Hernandez, smiled at him and did not apologize, according to prosecutors. Haggan said de Abreu and his friends did not appear to recognize Hernandez and had no idea he was upset.

Hernandez became increasingly agitated and told his friend that de Abreu had deliberately bumped into him and "was trying him," Haggan said.

Surveillance video outside the club shows Hernandez pacing back and forth on the sidewalk as his friend tried to calm him down, Haggan said. Hernandez and his friend then crossed the street to another nightclub, where Hernandez thought he saw de Abreu and his friends come in, according to Haggan.

Hernandez then told his friend he believed he was "being targeted and being disrespected," according to Haggan. In fact, de Abreu and his friends had not left the other club.

Haggan said Hernandez later drove around with his friend until he saw de Abreu, Furtado and others going to their car. He followed them and pulled up alongside their car at a red light.

"At this time, the victims were completely unaware there was any problem with the defendant," Haggan said.

Hernandez leaned out the driver's side, said "Yo, what's up now," followed by a racial slur, then fired at least five shots into the car, killing de Abreu and Furtado, and injuring a man sitting in the back seat, Haggan said.

Hernandez's attorney, Charles Rankin, objected, saying the prosecutor's account of the shooting was an attempt to poison the jury pool. Clerk Magistrate Gary Wilson dismissed the objection, saying it is standard procedure for prosecutors to describe evidence during arraignments in murder cases.

Family members of the victims filled four rows in the courtroom. One woman sobbed loudly as Hernandez entered his not guilty pleas.

De Abreu and Furtado were shot about six weeks before Hernandez signed a five-year, $40 million contract with the Patriots. He went on to catch 51 passes and score five touchdowns that season, his last in the NFL.

Hernandez, 24, was released by the Patriots last summer after he was charged in the June 17 killing of semi-pro football player Odin Lloyd, who was dating a sister of Hernandez's fiancee. Lloyd's body was found in an industrial area near Hernandez's home in North Attleborough.

Hernandez's lawyers have said he is looking forward to proving his innocence.

Suffolk District Attorney Daniel Conley would not comment when reporters asked if Lloyd's killing was linked to the earlier killings of de Abreu and Furtado. He said Lloyd was not the friend who was with Hernandez the night the two men were killed.

Hernandez will continue to be held without bail. He is due back in court June 24 for a scheduling hearing.