Justin Faltermeier told police that he only wanted to scare Blaine McNally when he threw a knife at him during a party at a Sherwood Park home in July 2009.

McNally, 18, was struck by the knife and died of a stab wound to his chest.

Faltermeier, then also 18, recounted what happened in an interview that same night with Cpl. Jason Reeve of the RCMP. Video of that interview was played Wednesday at Faltermeier's manslaughter trial in Edmonton.

In the video, Faltermeier is seen crying while he waits for Reeve in the interview room of the Strathcona County RCMP detachment.

He tells the officer that McNally had earlier threatened him with a knife, so he grabbed a knife of his own out of a kitchen drawer.

"I didn't mean to hit him," Faltermeier says in the videotape. "Obviously I meant for the handle to hit him and then that's it, and just scare him."

Faltermeier, who admitted several times to throwing the knife, told Reeve he was aiming for McNally's leg.

He tells the officer he believed he should go to jail and that he has screwed up his life.

Faltermeier again weeps and prays as he writes a letter of apology to McNally's family and an explanation of how the incident happened.

"God I'm so sorry, Blaine, I'm sorry ... How could I take a life away," he says.

Faltermeier was initially charged with first-degree murder but the charge was changed to manslaughter after the preliminary hearing.

The trial is to wrap up on Friday