HALIFAX -- An eyewitness said he heard a loud bang, and saw a bloody man sitting on a chair in the Halifax apartment of a medical student on trial for murder.

Pookiel McCabe told a Nova Scotia Supreme Court jury Monday that he was William Sandeson's close friend and neighbour on Aug. 15, 2015, the night Sandeson allegedly killed 22-year-old Taylor Samson.

He and a friend had been drinking in McCabe's apartment across the hall from Sandeson's. They were all friends and he and Sandeson had been track-and-field teammates at Dalhousie University.

"We heard, like, a bang," McCabe told the jury.

McCabe said Sandeson came to his door and "looked a little shocked," so they followed him across the hall and looked inside his apartment.

"I saw a man there sitting in a chair. He had blood on him," McCabe said. The man had his back turned to him and he didn't see his face, he said.

He remembered being in shock and couldn't recall much from the scene, but did say the man in the chair was white, with black hair, and was wearing shorts. He also said he saw blood and money on the floor.

"I didn't see him move," he said about the man in the chair.

On a surveillance tape, McCabe and his friend can be seen leaving the building shortly after they look into the apartment.

McCabe described his relationship with Sandeson as "close," after having known him for five years.

A surveillance video system set up by Sandeson caught Samson entering the apartment, and around five minutes later McCabe and another male looking in the doorway. There's no sound in the video, which was played for McCabe and the jury Monday.

Samson was last seen alive on the surveillance tape entering the apartment to sell 20 pounds of marijuana to Sandeson that night.

McCabe did not tell investigators he had heard the shot and seen the wounded man until his third interview with police.

"I was scared," he told the jury about his reluctance to tell them what he had seen.

There were rumours that Sandeson was connected to organized crime, he said. But he said he found out that wasn't true, and he then felt safer about telling investigators what he saw that night.

McCabe and Sandeson remained in infrequent contact since Sandeson was charged with murder, exchanging letters and speaking on the phone once. They didn't discuss the case, said McCabe.

McCabe signed off one letter saying, "the crew misses you and will always be here for you," referring to their mutual friends, he said. The letter was introduced by the defence as evidence Monday.

The trial resumes Tuesday morning.