A newly released report reveals more disturbing details about the murder of Oscar Grant, an unarmed black man who was fatally shot by police more than a decade ago. 

On New Year's Day 2009, 22-year-old Grant was forcibly pulled off a train by Bay Area Rapid Transit officers who were responding to reports of a fight. The father was struck multiple times and forced to lie face down on the Fruitvale train platform. Moments later, officer Johannes Mehserle shot Grant in the back.

Mehserle claimed the shooting was unintentional, as he meant to draw his Taser rather than his gun. A California jury accepted his explanation and charged Mehserle with involuntary manslaughter. He spent about seven months behind bars.

The incident also resulted in the termination of Anthony Pirone, a former BART officer who was accused of trying to conceal the details surrounding Grant's murder. Pirone was one of the first officers to encounter Grant at Fruitvale BART Station on the night of the shooting. Witnesses described him as a "crazy cop," and claimed he had screamed racial slurs at Grant shortly before Mehserle opened fire.

"Pirone was, in large part, responsible for setting the events in motion that created a chaotic and tense situation on the platform, setting the stage, even if inadvertent, for the shooting of Oscar Grant," read the report obtained by the San Francisco Chronicle

Pirone told authorities he was "fighting for my life" after Grant allegedly kneed him in the groin; however, a bystander's video of the incident did not support the ex-officer's claims. 

"None of this appears to have happened during the video," investigators wrote in the report.

An autopsy report also revealed Grant had suffered a hemorrhage during the incident, after he was kneed in the head—a detail Pirone failed to disclose to authorities.

"Pirone used force against Grant as a first resort and even then the use of force … did not appear reasonable, justifiable or excusable," the report stated. "[Pirone's] willful and reckless conduct … endangered the safety of the public."

The 144-page report was completed by Meyers Nave Law Firm, which led BART's internal investigation into the shooting. Outlets obtained the files under California's new police transparency law.

"The reports clearly show that because of the officers not deescalating a situation, but escalating a situation, my son is not here today," Grant's mother, Wanda Johnson, KRON4. "The people on the platform, you know, still, 10 years later, having to play that in their minds, over and over and over, unnecessarily."