In February 2008, 14-year-old Brandon McInerney and 15-year-old Lawrence King sat a row apart in 8th grade English.

A few days before Valentine's Day, McInerney brought a gun to school and shot and killed King in front of his classmates.

Why? The question remains without a full answer.

Lawrence King and Brandon McInerney (family handout/Ventura County Star)

Could the murder have been motivated by a schoolyard crush, one boy's frustrated attraction to another? Was it pure bullying, carried to the extreme? And, when the school allowed King to dress in women's clothing and wear make-up, did it lead to a blurring of the line between the bully and the bullied?

Three years later, McInerney, 17, was tried as an adult for first-degree murder and a hate crime. The prosecution argued he was a white supremacist who hated homosexuals and that he killed King because King was gay. If convicted, he could spend the rest of his life in prison.

Would a jury convict a boy — who at the time of the shooting was barely 14 — of first-degree murder and a hate crime? Or would they "blame the victim" for somehow, to some extent, inciting his own death?

ABC News' "20/20? goes inside one of the most controversial bullying cases of our time and asks: Who bullied whom? And, is there ever a reasonable explanation for murder — an 8th grade murder?

Check out the preview below and click here for more on this story.