SAINT JOHN, N.B. -- A man who probably heard Richard Oland being bludgeoned to death in his office has told a Saint John court he cannot pinpoint the time the strange thumping noises were made.

John Ainsworth's testimony at the second-degree murder trial of Dennis Oland on Thursday leaves open the possibility that the multimillionaire businessman was killed during his son's visit to the uptown Saint John office on July 6, 2011.

Ainsworth cannot corroborate the testimony of his friend, Anthony Shaw, who was also working in the building, below Richard Oland's office, on the evening of the killing.

Shaw said he believes he heard the thumping sounds sometime between 7:30 p.m. and 8 p.m. -- a time that would exclude Dennis Oland as the killer since he was caught on video shopping in a store on the outskirts of the New Brunswick port city.

But Ainsworth, who owns the building, said he cannot be more precise beyond saying he heard the noises sometime between 6 and 8 p.m.

Dennis Oland was visiting privately with his father in the second-floor office until 6:30 p.m. Police and prosecutors believe he killed his father "in a rage" over money issues during the visit.

Ainsworth and Shaw were working in Ainsworth's printing shop on the first floor when they both heard the thumps coming "through the ceiling" from the area of Richard Oland's office.

Ainsworth said there are just two times he is sure of: Shaw's arrival at the printing shop at "6ish" and the presence of a customer who sent a fax later that evening. The fax was time-stamped 8:11 p.m.

"Those are the benchmarks," he told the court. "Everything else is as nebulous as all get out."

Ainsworth said he heard a loud thump followed by what he described as "rapid fire" noises. He said he and Shaw did not investigate the sounds.

"It was so short-lived," Ainsworth said. "Maybe 10 to 12 seconds. It wasn't disconcerting … We kind of looked at each other and didn't think much of it."

Richard Oland, 69, was killed by over 40 blows, mostly to his head. A weapon was never found but the autopsy identified both sharp edge and round, hammer-like blows to Oland's head. Blood, bone and brain matter were sprayed around the room.

His only son, Dennis, an investment adviser, was charged with second-degree murder in 2013. He has pleaded not guilty.

Oland was convicted by a jury in 2015 but the verdict was set aside in 2016 and the new trial ordered. The current trial is before judge alone.

Crown prosecutors are close to concluding their case against Oland and may be able to wrap it up on Friday. The defence will cross-examine Ainsworth on Friday afternoon.

The defence is expected to present its case in a couple of weeks. Defence lawyer Alan Gold said he plans to ask the court to allow a visit to the crime scene for better visualization of the cramped conditions in the office.

Justice Terrence Morrison said such requests are not usually granted, but he said Gold is free to make the application.

In addition to Ainsworth's testimony, prosecutors are playing video of blood and DNA testimony from Oland's first trial in 2015.

Joy Kearsey, who worked extensively on the Oland case at the RCMP laboratory in Halifax, testified there were four confirmed bloodstains on the brown jacket Dennis Oland was wearing on July 6, 2011. Richard Oland's DNA was found in three of the stains.

Kearsey said the probability that those DNA samples would match another Caucasian male in the Canadian population was "one in 510 billion" -- a virtually impossible chance that the samples could belong to someone else.

Friday will be day 39 of the Oland retrial.