The lawyer for Frank Ostrowski, above, said Tuesday that his murder prosecution resulted in a wrongful conviction. (CBC)

The 1987 murder conviction of Frank Ostrowski, now being reviewed as a possible wrongful conviction, is only the latest example of systemic problems with Manitoba's prosecution service, a court heard Tuesday.

"There was some kind of systemic practice … so that witnesses could say things that were known only to one side in the adversarial system to be not true," Ostrowski's lawyer, James Lockyer, told Court of Queen's Bench Justice Colleen Suche.

"There was a pre-meditated decision … to conceal evidence from the defence."

Ostrowski, a hairstylist who became a cocaine dealer, was convicted of ordering the 1986 murder of informant Robert Nieman, another drug dealer. The Crown said Nieman was killed out of fear he was set to tell police about Ostrowski's cocaine operation.

Suche reserved her decision on whether to grant Ostrowski bail while the federal government reviews his conviction. Lawyers were told to expect a decision in about two weeks.

Ostrowski, who has always maintained his innocence, was convicted largely because of the testimony of Matthew Lovelace, a drug dealer who had cocaine charges against him dropped in exchange for his testimony.

That deal was never disclosed to the jury or the defence, and Lovelace testified he was not given any favours for his testimony.

"The jury was totally misled in this case," Lockyer said Tuesday. "It was just plain wrong."

Lovelace's lawyer has defended the way his client was handled.

Hymie Weinstein testified Monday that he negotiated the deal for Lovelace, but never told him about it so as not to taint his testimony.

Lockyer said there is no excuse for hiding facts from the defence.

Crown attorney Rick Saull said it was common practice at the time not to hand over every police document to the defence. He also said Ostrowski's trial lawyer had the opportunity to grill Lovelace about any deals.

"He went after Mr. Lovelace at length — a full-frontal assault during cross-examination."

Saull also said the disclosure of the deal may not have changed the outcome of the trial. He urged the judge to keep Ostrowski behind bars until the federal Justice Department is further along in its review.

Facts concealed in other cases

Ostrowski's case bears a striking resemblance to those against James Driskell, Kyle Unger and Thomas Sophonow, Lockyer said.

Important facts were concealed by the Crown and the accused were later exonerated after spending years in prison.

Driskell was convicted of killing a friend in Winnipeg in 1990, partly on testimony from Ray Zanidean — a witness who, unbeknownst to the defence, was given tens of thousands of dollars in expense payments and immunity on an arson charge for his testimony. Driskell's conviction was quashed in 2005.

Unger was convicted of killing a teenage girl at a rock festival in 1990. His conviction was quashed by the federal justice minister after DNA tests disproved the only physical evidence. Without the defence's knowledge, a jailhouse informant in the case was given special consideration for his help.

Sophonow was found guilty of killing Winnipeg waitress Barbara Stoppel in 1981, largely because of witness testimony that later turned out to be faulty. One witness's statement to police contradicted her testimony in court, but the defence never knew about the police statement and could not challenge the testimony. Sophonow spent four years in prison before he was freed on appeal.

In all three cases, the Crown's lack of disclosure was criticized in ensuing public inquiries.