It was an emotional morning in Nova Scotia Supreme Court Monday, as the girlfriend of the victim testified at the first-degree murder trial of a former Halifax medical student. The trial was also interrupted and delayed by lawyers making a legal argument.

Taylor Samson’s girlfriend, Mackenzie Ruthven, was emotional from the moment she took the stand. She testified she was in a relationship with Samson in the six months before he disappeared.

Ruthven told the court she last saw him on the evening of Aug. 15, 2015, at the apartment he had just started moving into in Halifax.

Ruthven testified Samson said he was going a couple of houses down and that he would be right back. She says she hasn't seen or heard from him since.

“Taylor Samson’s girlfriend is one of the last people we say that saw him alive, so we are obviously interested in having her tell the jury about the last time she saw him,” says Crown attorney Susan MacKay.

Former Halifax medical student William Sandeson is charged with first-degree murder, but Samson’s body has never been found.

Also taking the stand Monday was Sgt. Sandy Johnston, who was cross-examined on evidence she provided last week.

Sgt. Johnston was an officer in the Forensic Identification Unit in 2015. She showed the jury the gun and bullets seized from William Sandeson's apartment, as well as photos she says appeared to be blood spatter in the apartment.

The defence cross-examined her on the details of the investigation, much of which she couldn't recall.

“This is a case involving a lot of circumstantial evidence and the type of exhibits that she spoke about, the things that she saw in the apartment, would be very important,” says MacKay.

The Crown alleges Samson and Sandeson were doing a drug deal the night Samson disappeared.  Ruthven testified she had some knowledge of Samson's involvement in the drug trade, but that he tried very hard to keep it from her.

The defence asked her about what she told police about Taylor Samson’s medication for an autoimmune liver disease. She testified he could go long periods without taking it.

Soon, the cross examination was interrupted and the jury dismissed early while the lawyers argued a legal issue.

A publication ban protects anything that is said in the absence of the jury, so CTV News cannot say the specifics of the matter that delayed the trial, but it is expected to continue Tuesday morning.

With files from CTV Atlantic’s Kayla Hounsell