Opening statements were delivered well over a month ago, and nearly 80 witnesses have taken the stand since then. Here's a look back at some of the major events and testimony so far.
FALL RIVER - Attorneys for Aaron Hernandez are trying to convince the jury he did not kill Odin Lloyd in June 2013, while prosecutors are meticulously laying out the evidence that, even if he didn't pull the trigger, the former New England Patriots star was at the crime scene.
Under Massachusetts law, prosecutors don't need to prove Hernandez committed the murder, shooting Lloyd to death in an industrial park with the help of two accomplices. All they need to prove is "joint venture," meaning he intentionally participated.
Opening statements were delivered well over a month ago, and dozens of witnesses have taken the stand since then. Here's a look back at some of the major events and testimony so far.
Were Hernandez and Lloyd actually friends? And does it matter?
Defense attorney Michael Fee has repeatedly stated that Hernandez had no reason to kill Lloyd because they were dear friends. In fact, Fee argues, that would be all the more reason not to hurt him.
They met because Lloyd was dating Shaneah Jenkins, the sister of Hernandez's fiancee. Jenkins testified that the pair were cordial and smoked marijuana together, but they were not close. She said Hernandez and Lloyd never socialized outside her presence except on the night of the murder.
Even if they were friends, prosecutors say it wouldn't stop Hernandez from killing Lloyd. They've asked the judge to let them tell the jury that Hernandez is accused of shooting his friend, Alexander Bradley, between the eyes just four months before Lloyd's murder. Bradley survived and filed a lawsuit over the attack.
The judge has twice refused to allow that subject to be brought up.
Hernandez's DNA found at crime scene
The defense has acknowledged and even volunteered information about Hernandez's extensive marijuana use, saying Lloyd supplied him and the two often smoked together. But they do have plenty to say about the findings of a Massachusetts State Police crime lab analyst, who said DNA from both men was found on a marijuana cigarette butt left at the crime scene.
Diane Fife Biagiotti said the saliva on the rolling paper could have come from two different people, but the odds are extremely remote: Only 1 in 36.94 quadrillion in Hernandez's case.
Attorney James Sultan said that doesn't prove anything. The two could have shared the joint at another time.
Biagiotti also said her tests showed Hernandez's DNA on a shell casing that was found in the rental car allegedly used in the murder. She did not know that, before it was given to her for analysis, a piece of bubblegum had been stuck to it.
Sultan argued the DNA from Hernandez's chewed gum transferred to the shell casing when both were thrown into a trash container at the rental agency. He also pointed out that no DNA sample was taken from Ernest Wallace, one of the other suspects.
Tire tracks match Hernandez's rental car
Massachusetts State Police Trooper Todd Girouard ran into similar questioning from Sultan about his analysis of tire tracks found in the industrial park where Lloyd was killed.
Girouard said a track matched the rented Nissan Altima that Hernandez was allegedly driving that night. Prosecutors say he and the two other suspects, Wallace and Carlos Ortiz, picked up Lloyd in that car and drove him to his death.
Sultan jumped on Girouard's testimony by questioning his expertise, pointing out he had taken a single course in tire tracks in 2009 that lasted less than a week. This was his first court testimony on tracks, and his 15th analysis for a case.
The trooper was able to fend off some of Sultan's attacks on his credibility. He defended his methodology and refuted Sultan's claim that the weight inside a vehicle changes its tire tracks.
Text messages show increasing agitation
On June 16, 2013, Hernandez sent a text message to many of his friends, including Ernest Wallace, wishing them a happy Father's Day. Then he went out with his fiancee, Shayanna Jenkins, to celebrate.
Throughout the day, Hernandez's texts to Wallace became more anxious. He asked Wallace to come to his home in North Attleboro, Mass., from Wallace's place in Bristol, Conn., because he didn't want to spend the whole day with Jenkins.
Then, hours before the murder, Hernandez texted: "Get your ass up here." Prosecutors say Wallace made the drive with Ortiz, then they all prepared for Lloyd's murder in full view of Hernandez's home surveillance system.
Video shows Hernandez destroying his cell phone, using lawyer's
Surveillance video from the North Attleboro Police Department parking lot shows Hernandez dismantling his own cell phone and using his lawyer's to make a call to Wallace the day after the murder. Jurors were not told to whom the new phone belonged.
Detective Michael Elliott said he made the video after Hernandez came to the station that night.
Defense attorneys tried to get the judge to block the video from the trial, comparing the recording to a drone secretly spying on people.
Hernandez's fiancee granted immunity to testify
Prosecutors have said they believe Shayanna Jenkins got rid of the murder weapon, which still has not been recovered, and Judge E. Susan Garsh allowed her to be granted immunity in exchange for her testimony.
She is facing perjury charges over her grand jury testimony. Her defense attorney said she did not lie about guns in the couple's home; she was simply wrong.
Details of the prosecution's immunity request were sealed, so they are not available to the public.
Did Shayanna Jenkins ditch the gun?
Carlos Ortiz told police that, after the murder, Hernandez placed the .45 caliber Glock handgun into a box in his basement.
After suspicion fell on him, prosecutors say Hernandez sent Jenkins coded text messages telling her to get rid of a box in the basement, and video from their home surveillance system shows her doing so, putting it in her car and driving away. The contents of that box are not clear.
The white towel
On their way to pick up Lloyd, the three suspects stopped at a gas station. Hernandez, who had just rung up a $243 bar tab and smoked marijuana, is seen dancing near the pump, while Ortiz is seen with a white towel around his neck.
A white towel was found near Lloyd's body.
Biagiotti, the state police DNA analyst, said no DNA was found on the towel, and a hair yielded no testable sample.
Hernandez made babysitter uncomfortable, but they shared a kiss
Jennifer Fortier testified that she was the babysitter for Hernandez's and Jenkins' infant daughter. Two nights before the murder, Fortier and a friend ran into Hernandez and his friends, including Lloyd, in Boston's theater district and accepted their offer of a ride.
Fortier said she thought she was being driven to her own car, but instead they went to Hernandez's apartment in Franklin. The trip made her "uncomfortable" because of their business relationship and the fact that she didn't know Hernandez well: She always went through Jenkins.
At the apartment in Franklin, Hernandez and Fortier briefly kissed before Fortier stopped it. Then she called a car service and left.
Jury problems start early and continue
One of the more controversial pretrial matters was jury selection, which CNN argued was being conducted in a way that deviated from legal precedent.
Individual questioning of potential jurors, a process called voir dire, was conducted out of earshot of the public and the media at Hernandez's request.
A letter from CNN's attorneys to Judge Garsh included the following: "The values of openness are preserved only if the public is afforded the opportunity to hear the judge's questions as well as the potential jurors' responses."
Garsh rejected a request to open up the questioning, citing different case law than CNN.
Problems with the jurors continued even after all 18 (12 jurors plus six alternates) were seated and sworn in. In early February, one juror was kicked off the panel and another was dismissed.
The first juror was removed when it was alleged that she lied during the selection process, told people she wanted to be chosen, and said it would be tough to convict Hernandez since the murder weapon is still missing.
The second juror was excused for unspecified personal reasons.
What's going on now?
The prosecution has spent a great deal of time on Monday and Tuesday going over the intricate details of Hernandez's cell phone records. They're trying to show his state of mind, alleged collusion with other people before and after the murder, and his movements around that time.
What's next?
It's hard to tell who will be called to testify, when or about what, although there are several key witnesses who have not yet taken the stand. The most impactful could be Shayanna Jenkins. An immunity deal means she is required to be truthful or else face additional charges.
New England Patriots team owner Robert Kraft and head coach Bill Belichick are listed as potential witnesses, as are NFL players Brandon Spikes and Mike Pouncey.
What happens after the trial?
Whether he's found guilty or innocent in Lloyd's murder, Hernandez has a long legal road ahead of him. He's also charged with a double murder in Boston in 2012, assaulting a fellow inmate and threatening a guard, not to mention several lawsuits related to the murders and the Alexander Bradley shooting.
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