Before Judge E. Susan Garsh adjourned the second day in the murder trial of former New England Patriots star Aaron Hernandez with cautionary instructions to Super Bowl-watching jurors, graphic photos and testimony contradictory to the defence team's opening arguments caused an emotional scene inside a Massachusetts courtroom.

The prosecution continued calling witnesses on Friday, beginning with North Attleboro Fire Captain John White Jr.

White was among the first to witness the slain body of Odin Lloyd on June 17, 2013, and lawyers from both sides took turns examining his account of the murder scene, including the presentation of graphic photos showing in detail Lloyd's fatal gunshot wounds.

Ursula Ward, Lloyd's mother, was overwhelmed with emotion at the sight of the photos of her dead son and immediately exited the courtroom.

The murder weapon has not been found and Hernandez has pleaded not guilty to all charges.

Later in the day, Shaneah Jenkins, Lloyd's girlfriend and the sister of Hernandez's fiancee, took the witness stand and recited her knowledge of the relationship Hernandez and Lloyd shared.

Jenkins testified that the two were at "the beginning stages of a friendship" but weren't close at the time of Lloyd's murder.

That sentiment was contradictory to the case built by Hernandez's defence team during opening arguments claiming that Hernandez and Lloyd were "partying pals."

Jenkins, who studies criminal law at a Boston area law school, said Hernandez and Lloyd sometimes smoked marijuana together in Hernandez's basement. She said she met Lloyd in 2012 while working in Connecticut.

She is scheduled to resume her testimony on Monday.

At the end of the day, Garsh told jurors they will be allowed to watch the Super Bowl between the Patriots, Hernandez's former team, and the Seattle Seahawks on Sunday but cautioned that they must remain vigilant during the game to avoid mentions of the case that may crop up during the broadcast.

"I am not going to forbid you from watching the Super Bowl Sunday if that's something that's really important to you," Garsh said.