SAINT JOHN, N.B. -- After delays, a mistrial and dismissal of the jury, the retrial of Dennis Oland for the second-degree murder of his multimillionaire father will finally begin on Wednesday by judge alone.

The mistrial was announced Tuesday by Justice Terrence Morrison, citing "improprieties" in jury selection involving an officer with the Saint John police force.

Const. Sean Rocca accessed a police database to check on prospective and sworn jurors in violation of a 2012 directive from the Supreme Court of Canada concerning jury vetting.

"The Crown was not aware of these improprieties at the time they occurred. When the Crown found out, they immediately notified defence counsel," the judge told the New Brunswick Court of Queen's Bench jury as he announced the mistrial.

"I have determined that it is in the best interests of justice that a mistrial be declared thereby ensuring any further trial of this matter will not be tainted."

It turns out the internal police database was also used during jury selection for the first Oland trial in 2015 -- a jury that convicted the 50-year-old financial adviser of the second-degree murder of his father, Richard Oland.

That conviction was overturned on appeal in 2016 and the new trial ordered.

Rocca, the file coordinator for Crown prosecutors, was paying particular attention in his searches as to whether jurors may have had "negative interactions" with Saint John police.

"Obviously we were aghast, gob-smacked, to find out it had happened previously," chief defence counsel Alan Gold said Tuesday following the mistrial announcement.

"But our concern is what happens now and the future and getting this trial done as expeditiously as possible."

In a statement late Tuesday, the city's board of police commissioners said it would be asking the New Brunswick Police Commission to do an independent review.

"We will be reviewing the court's decision to understand the issues identified and to learn from them. The board and the chief take these matters very seriously," it said in a statement.

Oland will be re-arraigned in a Saint John courtroom on Wednesday and he will re-enter his not guilty plea. The trial, before Morrison, will then proceed with opening statements and possibly the first witnesses.

Oland, his wife Lisa and mother Connie were all in court for the news on Tuesday, the latest twist in a case that has seen many.

Oland is charged in the bludgeoning death of his father, Richard, a businessman and former executive with Moosehead Breweries Ltd. in Saint John. The 69-year-old's body was found on the morning of July 7, 2011, in a pool of blood on the floor of his office in the city's uptown. He had been struck over 40 times, mostly on the head, with a weapon that has never been found.

Dennis, his only son, is the last known person to have seen his father alive. He was charged in 2013, and has steadfastly maintained his innocence with the support of his family, including Connie, Richard's widow.

During the first trial, the Crown focused on possible issues of motive, including Dennis Oland's financial difficulties and the knowledge his father was having an affair.

But in his own testimony, Dennis Oland downplayed his finances as a recurring issue in the life of a financial adviser and said he never raised them with his father. He also said the two never discussed his father's affair.

The defence pointed to video that showed Dennis Oland and his wife shopping later on the evening of July 6, 2011, when people working below Richard Oland's office say they believe they heard the sounds of the murder.

The key piece of evidence for the Crown was a brown jacket worn by Dennis Oland that had a number of small blood stains and also DNA that matched the profile of Richard Oland. However, none of the expert witnesses could say how long the blood had been on the jacket or how it got there.

Yet there were some inconsistencies in Dennis Oland's story.

Dennis Oland had told police that he visited his father's office twice on July 6, and that he had been wearing a navy blazer. Testimony from witnesses and surveillance camera video showed him wearing a brown jacket, and it was eventually learned from Dennis Oland himself that he went back to the office a third time to retrieve a logbook for his uncle.

The Crown pointed to those inconsistencies when cross-examining Dennis Oland, who said at the time of his statement to police he was nervous and in shock.

The decision to proceed with judge alone should speed up the retrial, originally forecast to last four months with a jury.

"We can focus on the substance of the case," Gold said, adding the defence always wanted trial by judge alone -- a request previously opposed by the Crown.

"It makes for a neater, cleaner proceeding where you can focus on the merits, on the substance, and you don't have to worry about all of the incidentals that go with a jury trial."

Gold said the defence team is "extremely pleased" with the decision to proceed by judge alone. In fact, the Oland family, including Dennis, looked relieved on Tuesday with the announcement.

Gold said the missteps of the Saint John police force in relation to the Oland trial cry out for investigation by the New Brunswick Police Commission. The defence has long argued the police acted too quickly in deciding Oland was the killer.

Oland became the number one suspect for police just hours after the body was discovered.

"The New Brunswick Police Commission has many issues to examine about how this case was investigated and how the police decided Dennis was the perpetrator of the crime within hours of the murder being discovered," Gold said.

"The serious conduct that led to our jury selection being invalidated, and the jury trial nullified, can be added to that list of what needs to be examined in the interests of justice."

Steve Roberge, executive director of the commission, said in an interview he will be meeting soon with members of the oversight body to discuss the Oland case. He said a planned investigation had been put on hold once the new trial was ordered.

Roberge indicated it still would be best to wait for the trial to conclude.

The Oland beer-brewing family is both wealthy and prominent in the Maritimes.

Richard Oland left Moosehead in 1981, and was more recently president of the investment firm Far End Corp.

He also served as president of the board of the 1985 Canada Summer Games in Saint John, and was appointed an officer of the Order of Canada in 1998. He was also known as a competitive yachtsman and fitness advocate.

During jury selection, a longer-than usual list of questions was put to prospective jurors, including whether they believed the wealthy were given preferential treatment in the justice system.