HALIFAX -- A Dalhousie medical student told police two men dressed in black spandex morph suits came into his apartment, shot a drug dealer in the head, and then stuffed him into a black bag.

William Sandeson, 24, is on trial for the first degree murder of Taylor Samson -- who brought 20 pounds of marijuana to sell Sandeson -- before a Nova Scotia Supreme Court jury.

Over the last two days, the jury has seen Samson's girlfriend testify as well as an interrogation video of Sandeson on Aug 19, 2015, four days after the 22-year-old Samson went missing.

Throughout the taped interrogation, Sandeson remained mostly silent as Halifax Regional Police officers grilled him about what happened that night and Samson's whereabouts. His heavy sobs were audible as he rocked back and forth while they questioned him.

Sandeson gave varying versions of what happened in a series of police interviews -- included denying even seeing Samson, a fellow Dalhousie student, at all that night.

Then near the end of the video Wednesday, he said two men dressed in black spandex morph suits underneath street clothes came "to scare (Samson) out of dealing."

He said he knew they were waiting in his roommate's bedroom for Samson to get there, and when he showed up, "they had a gun on him."

They told Sandeson to shut off his surveillance system controlled from his own bedroom, he said, and then one of the men shot Samson in the back of the head.

"There was a lot of blood," he told the officer in the video.

"They put him in the bag with the weed," he said, adding they then left with the bag.

"It was the biggest bag I've ever seen," he said.

Sandeson told the officer he started to clean up the blood, putting paper towels and his shower curtain into black garbage bags and bringing them out to his car.

Earlier in the trial, the video showed Sandeson denying through heavy sobbing that he was the "mastermind" behind the drug meeting, but said he couldn't give the names of the two men.

"I don't have a name," he said.

In this version of events, Sandeson said he didn't know that the men were going to kill Samson. He also said the only witness to this was his next door neighbour, who poked his head in but only saw Samson sitting at the kitchen table where he was later shot.

On Tuesday, the jury heard testimony from MacKenzie Ruthven, Samson's girlfriend, who said that she saw him the day he went missing. She sent repeated text messages and phone calls when he didn't return the night of Aug 15.

The video of the interrogation ended with an officer coming in to the room and arresting Sandeson for murder.