Molitor, a brilliant Canadian amateur who won welterweight gold at the 1998 Commonwealth Games, is on trial for stabbing ex-girlfriend Nethery 58 times.
His guilt in her death was admitted during his lawyer's closing argument to the jury. But Molitor is only guilty of manslaughter - not the charge of second-degree murder, claimed the lawyer.
Molitor had told the court he stabbed Nethery after she stabbed him. He suffered cuts to three fingers, including one that required tendon surgery.
Professor Rosenbloom, a pharmacology professor, was presented with the "hypothetical" scenario by Molitor's lawyer of the use of three grams of cocaine, 20 ounces of alcohol and a serious hand wound inflicted by Nethery after he'd been awake for about 20 hours.
"Rational thought is decreased and emotionally driven action is increased," Rosenbloom said matter-of-factly.
Testimony from other witnesses had Molitor claiming to have done three grams of cocaine and that he was high.
Rosenbloom said three grams was a "huge amount."
The jury has retired to consider its verdict.
