Startling never-before-seen footage of the savage machete attack in a Bronx bodega last summer that claimed the life of a 15-year-old boy was presented by prosecutors on Tuesday, a day after the trial for five suspects charged with his brutal murder kicked off.

The second day of trial in the killing of Lesandro “Junior” Guzman-Feliz was emotional and filled with graphic video and photos.

Prosecutors introduced three clips of video. Two of the clips were taken by cell phone and show Guzman-Feliz outside the hospital and a high angle shot of the attack. The third clip is surveillance video outside the hospital.

One such graphic video presented was from the NYPD camera at the corner of Bathgate and 183rd Street in the Bronx — a corner that now bears Guzman-Feliz's name. The footage, which was never released publicly, shows the attack. The video showcases the attackers dragging Guzman-Feliz out of the bodega as he tries to fight back as the mob swings knives at him.

The graphic footage prompted Guzman-Feliz’s mother and several supporters to break down — a gasp was even heard in the courtroom.

Guzman-Feliz’s vicious killing shocked not only the city, but the nation, for its caught-on-camera brutality.

For a second day, a witness detailed more of Guzman-Feliz’s final moments.

The witness took the stand testifying how she tried to keep Guzman-Feliz alive by talking to him, adding that her friend took off their shirt in an effort to help stop the bleeding.

Defense attorneys subsequently cross examined the witness in an effort to test her memory.

The much-anticipated trial kicked off Monday with opening statements during which prosecutors described the teen's killing as a calculated and planned murder by the five suspects.

Five defense attorneys also spoke Monday, four of whom described most of Guzman-Feliz's wounds as superficial and said it was the one cut to the throat that killed him. The defense attorney for the man who allegedly dealt that throat cut took offense at that.

On Monday, a witness, the same that continued her testimony Tuesday, said she watched the attack from an apartment window and ran downstairs to try to help. She described, in heartbreaking detail, how Guzman-Feliz looked up at her after the attack and motioned her to call 911.

He only said one word -- "water," she testified.

Following her testimony Monday, it came to light that the district attorney's office placed the witness in protective custody after her name was released by some media outlets.

Jury selection proceedings started last month for five suspected gang members, the first of 14 to stand trial, facing murder charges in the June 2018 attack on Guzman-Feliz, who prosecutors have said was cut down at just 15 years old in an apparent case of mistaken identity.

Investigators say the group mistook Guzman-Feliz, who was not affiliated with any gang, for a member of the rival fraction of the Trinitarios gang. In total, more than a dozen suspects have been arrested in connection to the killing. Nine others charged in the killing are awaiting trial.

The attack on Guzman-Feliz was captured on video; he was dragged outside the bodega and set upon by a gang of men who hacked at him as he struggled to defend himself. The boy was slashed in the neck and died after running to a hospital three blocks away.

Guzman-Feliz had been part of the NYPD's Explorers program, a group for youths interested in a law enforcement career. The New York City Police Foundation announced it planned to set up a scholarship in his name.

Since the violent attack, the community’s outpouring of love and support has been seen in a mural. Guzman-Feliz’s memory has also been honored through the renaming of a street and a summer camp at a state park, as well as prompting the “Safe Haven Bodega” program in the city.