Hernandez, 23, was taken from his North Attleborough home in handcuffs just over a week after Boston semi-pro football player Odin Lloyd's bullet-riddled body was found in an industrial park a mile away.
Less than two hours after the arrest, the Patriots announced they had cut Hernandez, a 2011 Pro Bowl selection who signed a five-year contract last summer worth $40 million.
Lloyd was a 27-year-old athlete with the Boston Bandits who was dating the sister of Hernandez's fiancee. He was shot multiple times on a secluded gravel road, authorities said.
Hernandez "drove the victim to that remote spot, and then he orchestrated his execution," prosecutor Bill McCauley said.
If convicted, Hernandez could get life in prison without parole.
"It is at bottom a circumstantial case. It is not a strong case," his attorney, Michael Fee, said at a court hearing during which Hernandez was ordered held without bail on murder charges and five weapons counts.
Lloyd's family members cried and hugged as the prosecutor outlined the killing. Two were so overcome with emotion that they had to leave the courtroom.
McCauley said the slaying stemmed from a night out at a Boston club called Rumor on June 14. He said Hernandez was upset about certain things, including that Lloyd had talked to some people Hernandez "had troubles with." The prosecutor did not elaborate.
Two days later, McCauley said, on the night of June 16, Hernandez texted two friends from out of state and asked them to hurry back to Massachusetts.
Surveillance footage from Hernandez's home showed him leaving with a gun, and he told someone in the house that he was upset and couldn't trust anyone anymore, the prosecutor said.
The three men picked up Lloyd at his home around 2:30 a.m., according to authorities. As they drove around in their rented car, they discussed what happened at the nightclub, and Lloyd started getting nervous, McCauley said.
Lloyd texted his sister, "Did you see who I am with?" When she asked who, he answered, at 3:22 a.m., "NFL," then, a minute later, he sent one final text: "Just so you know."
Within a few minutes, people working the overnight shift at the industrial park reported hearing gunshots, McCauley said. Surveillance video showed the car going into a remote area of the industrial park and emerging four minutes later, the prosecutor said.
A short time later, Hernandez returned to his house, and he and one of the other men were seen on his home surveillance system holding guns, McCauley said. Then the system stopped recording, according to the prosecutor.
Hernandez had recently installed the system and had 14 cameras inside and out, according to McCauley, who said detectives found footage was missing from the six to eight hours after the slaying.
Investigators did not specify who fired the shots. They did not identify the two other people who were with Hernandez or say whether they were under arrest.
According to McCauley, Hernandez and his friends later returned the car to the rental agency, and Hernandez offered the attendant a piece of blue chewing gum. She found a .45-caliber shell casing and a piece of what appeared to be chewed blue gum in the car and threw them out.
Later, investigators retrieved the items from a trash bin, and the casing matched others found where Lloyd was killed, McCauley said. The two weapons seen on the surveillance footage have not been found, he said.
In arguing unsuccessfully for bail, Hernandez's attorney said the athlete is unlikely to flee, is a homeowner, and lives with his fiancee and an 8-month-old baby. He also said Hernandez had never been accused of a violent crime.
As he was led from his home in the morning, Hernandez was wearing a white V-neck T-shirt, with his arms inside the shirt and behind his back. He spit into some bushes on his way to a police cruiser.
Later, as he was taken from the North Attleborough police station to court, two dozen supporters cheered, some yelling, "We love you, Aaron!"
"Words cannot express the disappointment we feel knowing that one of our players was arrested as a result of this investigation," the Patriots said in a statement announcing he had been cut.
The team added: "We realize that law enforcement investigations into this matter are ongoing. We support their efforts and respect the process. At this time, we believe this transaction is simply the right thing to do."
The Patriots drafted Hernandez, who is originally from Bristol, Conn., in 2010 out of the University of Florida, where he was an All-American.
During the draft, one team said it wouldn't take him under any circumstances, and he was passed over by one club after another before New England picked him in the fourth round.
Afterward, Hernandez said he had failed a drug test in college -- reportedly for marijuana -- and was up front with teams about it.
In other off-the-field troubles, a Florida man filed a lawsuit last week claiming Hernandez shot him in the face after they argued at a strip club in February.
And The Boston Globe reported that Hernandez lost his temper and threatened a teammate during an argument in the team's weight room shortly after he was drafted.
Hernandez became a father on Nov. 6 and said he intended to change his ways: "Now, another one is looking up to me. I can't just be young and reckless Aaron no more. I'm going to try to do the right things."
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