Warning: This article contains disturbing details that may be triggering to readers. The murder trial of an Orillia man accused of stabbing his girlfriend’s former partner is underway in a Barrie courtroom. The jury heard the startling details of the case made by the Crown in its opening remarks, as Brian Lancaster stands charges with second-degree murder in the Dec. 2023 killing of Kyle Farrows. RELATED: Pair charged with second-degree murder in Orillia man’s death Lancaster, who turns 39 in August, sat beside his lawyers Brendan Monk, Alison Craig, and Tamar Bitton, accused of stabbing Farrows about two dozen times inside Farrows’ downtown Orillia apartment. The jury will have to determine whether Lancaster’s actions on the night of Dec. 14, 2023, were legally justified, overkill, or cold-blooded murder. Farrows was discovered lifeless in his bed covered in blood by a friend the following day. RELATED: Preliminary hearing begins for man accused in Orillia murder case The Crown said Lancaster killed Farrows while staying at his place with his then-18-year-old girlfriend Mackenzie Harrod, who had previously dated Farrows. Lancaster and Harrod knew Farrows still had feelings for Harrod and lied to him about their relationship. They told Farrows that Lancaster was her older brother. Harrod and Lancaster were both addicted to crack and homeless at the time, the Crown said. RELATED: Woman, 18, facing second-degree murder charge in Orillia man’s death granted bail According to the Crown, Lancaster admitted he stabbed Farrows after hearing Harrod scream while being held down by Farrows in his bedroom. Lancaster told police he saw Farrows holding a knife to Harrod’s throat, about to sexually violate her. Lancaster said he intervened and wrestled the knife away. While the men were fighting on the bed, Harrod, admitted to hitting Farrows in the head with a bong to help Lancaster gain the upper hand. Lancaster told police he was cut a few times while trying to grab the knife. He told a detective both he and Harrod stabbed Farrows but remained in the apartment until a friend returned the next day. The couple told the woman that Farrows had left the apartment after having a mental breakdown. The woman then booked them a room at a nearby hotel. Hours later the woman, who had a key to the apartment, discovered Farrows’ body and called police. RELATED: Midland woman convicted in ex-boyfriend’s deadly stabbing seeks house arrest conditional sentence Harrod took a plea deal earlier this year, for being an accessory after-the-fact to murder and was sentenced to house arrest. RELATED: Ont. woman charged with murder takes plea deal ahead of Orillia stabbing trial Lancaster, who has been in custody since his arrest, has a lengthy criminal record that included convictions for arson and assault. In 2014, he sexually assaulted a 15-year-old girl in her bedroom during a home invasion. The court heard testimony from a psychiatrist who said Lancaster was a moderate to high risk to reoffend. Lancaster argued he was high on drugs at the time of the assault. The trial is scheduled for three weeks before Justice Laura Bird.