Halifax medical student William Sandeson lured Taylor Samson to his apartment and shot him in the back of the head during a drug deal as part of a scheme to alleviate his debt, a Crown lawyer argued Tuesday.

Sandeson is charged with the first-degree murder of Samson, a 22-year-old Dalhousie University student whose body has never been found.

The jury trial has heard Samson went to Sandeson's apartment on Aug. 15, 2015 to sell him nine kilograms of marijuana for $40,000.

But in her closing arguments Tuesday in Nova Scotia Supreme Court, Crown lawyer Kim McOnie suggested Sandeson never intended to buy the drugs -- he planned to steal them.

"We suggest that Mr. Sandeson hashed a plan to alleviate some of his financial difficulties. He lured Mr. Samson to his apartment," McOnie told the jury, adding the Crown believes Samson was shot in the back of the head while seated at Sandeson's kitchen table.

"Taylor Samson had no clue what he was walking into to."

McOnie noted Sandeson, 24, told police three different versions of what happened that evening, including one version in which two men in morph suits busted into the kitchen to scare Samson out of drug dealing.

She suggested none of those versions are true. McOnie said Sandeson repeatedly changed his story to fit the information police confronted him with, and that evidence presented at the trial disproves each of his versions.

She argued the totality of the evidence points to one person: Sandeson.

"This is not a Hollywood film, where masked invaders or morph-suited intruders bust in through a window, shoot someone and take the body with them. This is reality," McOnie told the jury, urging them to find Sandeson guilty of first-degree murder.

"We believe Mr. Sandeson dragged Taylor down to the bathroom, that he somehow dealt with his remains in a way that he was able to fit them into a bag... We suggest Mr. Sandeson took Taylor out of the apartment that night in a black duffel bag while the DVR footage was off. We believe he disposed of Mr. Samson's remains."

Court has heard Samson was last seen alive on video that night, walking into Sandeson's apartment shortly before 10:30 p.m.

DNA matching Samson's was recovered from a bullet, gun, duffel bag and other items seized from Sandeson's Henry Street apartment in Halifax and his family's farm in Truro, McOnie noted.

She argued Sandeson -- who was slated to start medical school at Dalhousie University within a week of his arrest -- was motivated by money, noting he was in debt and that police only recovered roughly $7,200 cash.

The trial has heard Sandeson was in debt and under pressure from his parents about his spending in the weeks before he allegedly murdered Samson. Sandeson owed roughly $72,000 on a $200,000 line of credit, the jury has heard.

On Monday, defence lawyer Eugene Tan said in his closing arguments that the Crown twisted evidence in the case to fit its theory. He asked the jury to acquit his client, saying the Crown has made Sandeson out to be a "criminal mastermind."

But McOnie dismissed that assertion.

"Maybe Mr. Sandeson believed he was. We don't. He doesn't have to be a criminal mastermind to have committed first-degree murder," she said as Sandeson sat at his lawyer's bench listening intently.

"A plan to murder someone doesn't have to be a good plan."

Tan conceded there was a "violent incident" at the apartment that night, but said Sandeson maintains there was someone else who was also at the apartment.

Justice Josh Arnold is expected to give his closing instructions Thursday morning. The jury will then be sequestered to begin deliberations.