The trial of a 23-year-old Kings County man charged in the drug overdose death of another young man continued Wednesday in Kentville provincial court with testimony from a medical examiner.

Kyle David Fredericks, of Kentville, is charged with criminal negligence causing death and trafficking in a controlled substance in the death of Joshua Graves.

Graves, 21, died after taking a lethal mix of alcohol and Dilaudid at a house party nearly two years ago in the Annapolis Valley, which was also attended by Fredericks.

Dr. Marnie Wood took the stand on Wednesday and confirmed Graves died as a result of combined poisoning from alcohol and hydromorphone.

She said Graves' blood alcohol level suggested alcohol alone was not enough to kill him, while the level of hydromorphone in his blood could have been fatal on its own.

Wood testified alcohol and hydromorphone multiply each other's effects, causing breathing to slow or stop, leading to fatal brain damage.

Court watches videotaped interview

Earlier this week, court heard Graves drank about ¾ of a quart of rum at a party he attended just prior to his death. He was found unresponsive the next day, on March 19, 2011.

Wood said Graves' time of death is impossible to determine — he died sometime between 3 a.m. when he was last heard snoring and 3 p.m. when his body was discovered.

It's also impossible to say precisely when Graves took the hydromorphone, Wood said. She testified he could have taken the drugs more than 40 hours before he died, which would have been at least a day before he attended the party in Berwick.

Court then saw a videotaped RCMP interview with Fredericks after he was arrested for trafficking in a controlled substance.

Fredericks could be seen crying in the video and repeatedly denies giving Graves any Dilaudid. After an extended interrogation, Fredericks admits in the video to selling Dilaudid that night at the party, but not to Graves.

As the video continued, Fredericks eventually tells police he gave Graves half of a Dilaudid pill.

But when he took the stand, Fredericks denied he gave Graves anything, saying he lied to police in the video. He testified he lied because he was in withdrawal during the interview and felt pressured to admit to something so it would end.

The trial is adjourned until next Wednesday for arguments about the admissibility of the Fredericks police interview. The defence could introduce new evidence at that time.

Fredericks' trial is expected to last until the end of the week.

He was charged after Graves' sister, Amy Graves, mounted a public campaign urging police to reopen the investigation into her brother's death.