The jury in the Dennis Oland murder trial heard on Wednesday about searches, seizures and surveillance conducted by the Saint John Police Department.

Included in the footage was surveillance of Derek Oland, Richard Oland’s brother and the top man at Moosehead Breweries.

In February and March of 2015, as part of the Oland murder investigation, Const. Shawn Coughlan spent nine days following Derek Oland.

Police were trying to get a so-called ‘cast-off’ DNA sample from an item Derek Oland may have drank from.

"We watched in the area of Moosehead Brewery and we watched the area of his residence in Lepreau," said Coughlann to the jury.

In a statement earlier in October, Derek Oland said, “I was not asked for and did not refuse to provide a DNA sample to the Saint John police force. I was, and still am, willing to help with the investigation into my brother's death in any way possible."

The court heard that police were successful in obtaining a DNA sample from Bob McFadden, a business associate of Richard Oland. They seized a straw used by the man at a Saint John restaurant.

The jury has not heard why police wanted DNA samples from the men.

There were also more details Wednesday on an underwater search conducted in the days after the murder.

Const. Coughlan testified that a five-man dive team spent hours searching the waters around the Renforth Wharfin Rothesay. They were searching primarily for the murder weapon, but in the end, all they came up with was debris from the riverbed.

Coughlin was also asked to examine three computers seized from Dennis Oland's home – a personal computer and two laptops. He looked at the contents and the browsing history of the devices.

Defence lawyer Alan Gold asked about what police found on Oland's computers.

"So you're looking to see if someone has left a digital trace of an intention to commit a crime,  but you found nothing?" he asked.

“Correct,” Coughlin responded.

Richard Oland’s body was found on his office floor in a pool of blood on July 7, 2011.

Dennis Oland, 47, who was the last known person to see his father alive, has pleaded not guilty to second-degree murder in his death.

With files from CTV Atlantic’s Mike Cameron.