HALIFAX -- Medical student William Sandeson was panicked and incoherent as he tried to clean up around a man's blood-covered body in his apartment, a Halifax jury heard Thursday.

Justin Blades said he was a track-and-field teammate of Sandeson's who was visiting a mutual friend across the hall when he heard a gunshot on Aug. 15, 2015.

He and Sandeson's neighbour, Pookiel McCabe, were having drinks and smoking marijuana in McCabe's apartment.

Sandeson had been with them but left the apartment shortly before they heard a loud noise, Blades said.

"We heard a loud bang, real loud," said Blades.

"(I) froze for a second, jumped up, ran to the door, locked it," Blades said.

Sandeson came over about a minute later and knocked on the door but said nothing to the two men, said Blades.

"He just turned around and went back into his apartment," he said.

He told the Nova Scotia Supreme Court jury that he looked into Sandeson's apartment and saw a pool of blood, bloody cash, drugs, and a slumped-over body in a chair, bleeding from the head.

"Pints and pints of blood all over the floor," Blades said, his voice trembling.

Blades said he left and returned to McCabe's apartment.

He looked in again minutes later and saw the body had been moved, and streaks of blood going toward the bathroom.

"(Sandeson) asked me to bring the car around and I said no (expletive) way," Blades said.

Sandeson, 24, is accused of murdering Taylor Samson, 22, a fellow Dalhousie University student, during a deal to buy 20 pounds of marijuana.

Blades told jurors Sandeson was running around the apartment "in panic mode ... picking up bloody money."

Besides asking him to get the car, all Sandeson was saying was, "I gotta clean up," but was mostly incoherent, said Blades.

Blades said blood covered half the floor in Sandeson's kitchen.

"It's an abundance of blood. All over the floor," he said.

"I didn't even know what to say to Will," said Blades, who said he didn't call police right away because he was "in shock."

"You don't expect the nicest, most educated, one of the better people out of the group to do something like that," he said.

That night he didn't sleep, and said his life was never the same again.

Because of the high profile nature of the killing, coworkers and others gossiped about the case and "I had to leave my career," he said.

He said he carried the memory of that night like "the plague," and "didn't know what to do after so long."

He was scared Sandeson was involved with organized crime because of stories he had told Blades in the past, he said.

"I went off the map, no one knew where I was," he said.

Blades gave two statements to police in August, 2015, but didn't reveal what he had seen until October the following year.

He said Thursday he was too scared: "I felt like my life was in danger."

Defence lawyer Eugene Tan questioned Blades about the Oct. 20, 2016, statement, in which he told police he didn't believe Sandeson was the shooter.

"I don't know what you want me to say," Blades told Tan Thursday. "I don't know what happened."

He told Tan he remembered everything from the night in question.

"When you see a horrific scene like that, it's burned into your head," he said.