SAINT JOHN, N.B. -- The lack of physical evidence connecting Dennis Oland to the scene of his father's bloody murder and no clear motive means the jury deciding his fate must find him not guilty, the defence argued Monday.

Both sides made their final arguments to the jury on the same day, with Crown attorney P.J. Veniot telling the Court of Queen's Bench that Dennis Oland was the last person to see his father alive and had opportunity to kill him.

"The identity of the person who killed Richard Oland is known to you. It's Dennis Oland," he said.

"The Crown submits it cannot be anyone else."

But defence lawyer Alan Gold said the jury should reach a not guilty verdict, adding that at the end of the three-month trial they are no closer to knowing who killed Richard Oland than they were at the start.

Dennis Oland pleaded not guilty to second-degree murder in the death of his father, well-known businessman Richard Oland.

The 69-year-old was found face down in a pool of blood in his Canterbury Street office in Saint John, N.B., on July 7, 2011. The jury has heard he suffered 45 blunt and sharp-force wounds to his head, neck and hands, though no weapon was ever found.

Gold said the Crown hasn't produced a "shred of evidence that would produce the kind of emotion that would lead to the brutal killing of Richard Oland."

The police investigation found no forensic evidence to point to Dennis Oland, he said. The hairs found in Richard Oland's hands did not match his son's DNA and there was nothing under the elder Oland's fingernails to implicate Dennis Oland, Gold said.

There was also no blood or DNA evidence in Dennis Oland's car, on a reusable grocery bag he carried to and from his father's office the evening of July 6, 2011, or on his Blackberry, which he used to take a call from his wife at 6:36 p.m. that night, Gold said.

There was no drip trail or clean-up at the scene of the murder, he continued, and no evidence at the Renforth wharf or on his wife's boat, the Loki.

"Never have so many searched so long to find so little," Gold said.

In his argument, Veniot used Dennis Oland's mounting debt load and decreasing income as a possible motive for murder. He told the jury that Richard Oland was worth about $36 million at the time of his death and was tight with his money, while his son was spending well beyond his means.

"There was nowhere left for the accused to turn except to Richard Oland," said Veniot, who opened his case in mid-September by telling the jury the elder Oland had bankrolled his son's costly divorce from his first wife.

"There are only so many times you can go to the bank of daddy before being declined."

He focused as well on a text message received by Richard's Oland phone at 6:44 p.m. on July 6, 2011, which pinged off a tower in Rothesay. Experts testified that it probably wouldn't have pinged off a tower in Rothesay if it was still in Richard Oland's office.

As a general rule, Veniot said a cellphone connects to the nearest tower. None of the messages sent after 6:44 p.m. were received by Oland's phone and there were no replies after 6:44 p.m. because by that time Richard Oland was dead, he said.

Gold discounted the value of the cellphone evidence, telling the jury it isn't known where a cellphone call will connect.

Oland's iPhone has never been found.

"It's just a mystery in a case with many mysteries," Gold said.

He also dismissed the Crown's suggestion that Dennis Oland's financial hardships were motive enough to prompt a murderous rage.

Gold said financial difficulties were nothing new for Dennis Oland, noting he had equity in his home and would have had no trouble getting money from the bank. He was also able to get more money from his employer, he said.

Gold also reminded the court that employees of Printing Plus, one floor below Richard Oland's office, heard a crash and rapid thumping on the floor above between 7:30 p.m. and 8 p.m. on July 6, 2011.

"Those noises had to be the brutal murder of Richard Oland," said Gold.

He said the jury was shown security video of Dennis Oland and his wife Lisa shopping in Rothesay at that time.

Veniot told jurors the two men at Printing Plus were uncertain about the time, testifying that they could have heard the noise anywhere between 6 p.m. and 8 p.m. There was no evidence, he said, that either man looked at a clock.

Gold said his client was forthright in his testimony. He said if Oland wanted to lie, he wouldn't have told the jury he went back to his father's office a third time on July 6 despite telling police he went back only twice.

Oland also told police he wore a navy jacket that day, although he could be seen in security video shown during the trial wearing a brown jacket. Gold described the conflicting account as an "honest mistake."

Court has heard that the brown sport coat had three blood stains on it that were barely visible to the naked eye and DNA samples taken from the jacket found at Dennis Oland's home matched the profile of his father.

Oland's wife took the jacket to be dry cleaned the day after police said he was a suspect in his father's death, but Gold called that a "giant red herring." The dry cleaners testified that they examined the jacket but found no stains and didn't use any stain remover, he added.

Gold said the three blood stains were minuscule. "These were virtually invisible, tiny dot stains," he said.

Various security camera videos show no evidence of someone who had just committed a brutal murder, Gold said.

"You see an innocent looking person," he said.

Justice John Walsh is scheduled to begin giving his charge or intructions to the jury Tuesday morning. He has told the jury that will take much of two days to complete.