SAINT JOHN, N.B. -- A tense cross-examination of the final prosecution witness at the Dennis Oland murder trial has raised new questions about the time Richard Oland was killed.

John Ainsworth, the owner of the uptown Saint John building where Richard Oland was murdered on July 6, 2011, was grilled by defence lawyer Alan Gold on Friday about the loud thumps and bangs he heard that evening.

The noises likely were the sound of Oland being bludgeoned to death.

Ainsworth insisted, angrily at times, that he does not know what time he heard the noises, beyond the general range of 6 to 8 p.m. That is in contrast to his friend, Anthony Shaw, who was with him that evening and believes the noises were made around 7:30 to 8 p.m.

The time is critical to Dennis Oland's defence. If Shaw is right, the killer could not have been Oland, since he was caught on security video shopping at 7:30 p.m. Ainsworth's testimony leaves open the possibility that the killing happened while Dennis Oland was at his father's office, before he left at 6:30 p.m.

"I do not know what time it was," Ainsworth exclaimed under intense questioning by Gold. "I have been suffering with it for eight years. I do not know."

However, a videotaped statement made under oath by Ainsworth in 2011 for a private investigator working for the Oland family and entered into evidence on Friday, makes it clear that originally, Ainsworth also thought the sounds were made at 7:30 to 8 p.m.

"It was approximately 7:30, or quarter to 8," he said during the interview.

Despite that, Ainsworth said once he had time to reflect on what had happened, he felt he could not be specific about the time.

"I was not paying attention," he said.

Gold accused Ainsworth of wanting Oland to be convicted for the murder and that is why he backed off his original statement. But Ainsworth disputed that allegation.

"I am not that type of person," he said. "I want to be honorable. That's all. Integrity is everything."

The testy exchanges between Gold and Ainsworth closed the prosecution case against Dennis Oland.

Among the issues explored by Crown prosecutors: A bloodstained jacket, a missing cell phone, a multitude of police errors and the bludgeoned body of one of the wealthiest men in New Brunswick.

"There's no question that Richard Oland was murdered on July 6, 2011. The one major issue to be decided is whether it was Dennis Oland who committed this murder," prosecutor Jill Knee said in her opening statement when the trial began in November, 2018.

Other prosecution evidence on Friday included testimony from blood and DNA analysts who identified four small bloodstains on the jacket Dennis Oland was wearing when he visited his dad on the day of the murder. Richard Oland's DNA profile was found within three of the bloodstains.

But Gold said during cross examination of the forensic experts there are limitations to the blood and DNA evidence - there is no way to know when or how they came to be on the jacket.

"We can't say when DNA was deposited, how it was deposited, the order in which it was deposited or how long it was there," Thomas Suzanski, a forensic specialist from the RCMP crime lab in Ottawa, said in his testimony.

Suzanski's evidence, like that of several other witnesses, was presented to court by replaying video from Oland's first trial in 2015. He was found guilty of second-degree murder by a jury in 2015, but the verdict was set aside on appeal and the new trial ordered. The current trial is before judge alone.

The most contentious portion of the Crown's circumstantial case involved the investigation of Oland's killing by the Saint John police department.

The first few weeks of the trial included admissions from senior officers that insufficient measures were taken to protect the crime scene. The court heard about officers visiting the scene to view Oland's body as though it was a tourist attraction. Few of the visiting officers wore protective gear.

As well, a former deputy police chief, Glen McCloskey, was accused by an officer of attempting to have him alter his testimony to conceal the fact the senior officer was at the scene. McCloskey denied the allegation, but admitted he viewed the body a second time purely out of "professional curiosity."

Defence lawyers also argued that police did not sufficiently investigate a possible back door escape route from the crime scene and there was a rush to judgment in deciding Dennis Oland was the prime suspect just hours after the discovery of his father's body on July 7, 2011.

The Crown laid out evidence suggesting that money was the motive for the killing. Prosecutors said Dennis Oland was on the edge financially when he visited his father on the day of the murder.

He had previously borrowed heavily from what a defence lawyer once called "the bank of daddy" and was making interest-only payments to his father on a loan of more than $500,000. One of his cheques had bounced shortly before his visit to the office on the day of the killing.

Other key evidence in the prosecution case included Richard Oland's missing cell phone - the only item taken from the crime scene.

Cell phone records indicate the missing phone received its last message at 6:44 p.m. on the day of the murder. Experts told the court it pinged off a tower in Rothesay, on the outskirts of Saint John.

Dennis Oland told police he left his father's office at about 6:30 p.m. that day and immediately headed to his home in Rothesay.

The phone, like the weapon used in the killing, has never been found.

The stage now is set for the defence portion of the Oland trial, which will begin on March 5. Gold already has told the court that Dennis Oland will testify in his own defence, as he did at his first trial.