KELOWNA, B.C. - The first day of public testimony at the first degree murder trial of 27-year-old Matthew Foerster heard a fingernail clipping and a taped confession will form the core of the Crown's case.

Crown council Frank Caputo made his opening statement yesterday in B.C. Supreme Court in Kelowna, where Foerster is charged with the 2011 Halloween night attack on 18-year-old Taylor Van Diest.

The jury has been told Foerster's DNA was found in fingernail clippings taken from Van Diest shortly before she died and they will also hear the taped conversation where Foerster admits to police that he killed the teenager.

The first RCMP officer on the scene has testified Van Diest was gasping for breath when he arrived and she had a deep gash on the side of her head.

Caputo told the jury a pathologist later found Van Diest was severely choked during the attack and several blows to the top of her head likely caused her death.

The Crown expects to call 16 witnesses during the trial, which is expected to run for three weeks.