Cpl. Jody Allison, the RCMP officer seen in a police video interviewing William Sandeson, took the stand Wednesday along with another officer at the murder trial of the former Dalhousie University student.

Allison told the court that he was part of the Major Crime Unit in August 2015. He became involved in the case on Aug. 18, 2015, when he was asked to interview Sandeson.

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

Allison testified he interviewed Sandeson for nearly nine hours. The video of Sandeson being questioned had previously been played in court for the jury.

Allison also told the jury Sandeson's demeanour changed, that sometimes he was very emotional and sometimes calm during the interrogation.

The defence crossexamined Allison about his interview techniques.

He explained he used several props to aid the discussion, like the oath sworn by physicians and photos of Taylor Samson, whose body has never been found.

Sgt. Andre Habib also testified at the trial Wednesday. Habib says his main job was to sift through cow manure while teams searched Sandeson’s family farm in Lower Truro, N.S. on Aug. 28 2015 after cadaver dogs indicated there may be something there.

Habib told the cadaver dogs also led officers to a pond. The pond was drained but nothing was found.

The jury was shown photos of an ice cream truck on the Sandeson family farm, in which police found a blue Adidas bag and garbage bags. Inside the bags was a shower curtain, some cloths, and disinfectant spray. Nearby, more garbage was found, including a bank letter addressed to William Sandeson.

Court has previously heard from two witnesses who said they saw a man slumped over a chair inside Sandeson’s apartment the night of Aug. 15, 2015.

Pookiel Mccabe, who lived across the hall from Sandeson, and his friend Justin Blades both testified that they had seen a pool of blood, bloodied money, and drugs on the floor in Sandeson’s kitchen.

William Sandeson has pleaded not guilty. Testimony continues Thursday.

With files from CTV Atlantic’s Kayla Hounsell