When Hastings police encountered Matthew Jensen, he was nearly passed out, groaning in the passenger seat of his girlfriend's car, his eyes rolled back in his head and white foam oozing from his mouth.

A friend said Jensen had just injected heroin into his arm. Officers found a spoon with white residue next to the unresponsive Jensen. A plastic baggie with a brown powder was found in his friend's purse and confiscated.

In charging Jensen in the July 15, 2009, incident, Dakota County prosecutors say testing by the St. Paul police crime lab proved the substance police found on the spoon and in the baggie was heroin.

But now the validity of that claim -- and of thousands of other cases handled by the St. Paul crime lab over the years -- have come into question after revelations last week of shoddy work and unsound practices.

County attorneys, defense lawyers and the judicial system are preparing for a possible avalanche of new filings and hearings as defendants seek to get their convictions overturned because of the lab's supposedly shoddy work for prosecutors.

"If they are all tainted, then we have a massive problem, unprecedented in the state of Minnesota," attorney Marshall Tanick said. "If there are a number of these cases, it will be a very expensive proposition for the taxpayers."

The accusations about the St. Paul lab were made in Dakota County District Court by Jensen's attorneys, Lauri Traub and Christine Funk, who are challenging the St. Paul lab's work in eight drug cases. In testimony last week, lab staffers admitted to numerous shortcomings that threw its science into doubt.

"It was egregious," Pete Orput, the Washington County attorney, said when asked to comment on the lab's behavior. "This was to me a shock."

As a result, the head of the lab has been replaced and St. Paul Police Chief Thomas Smith has initiated a variety of changes at the facility. He also has asked prosecutors to review cases, past and present, for any possible problems caused by his lab.

The St. Paul case is one of several in which police crime labs in cities such as Detroit, Houston, San Francisco and Oklahoma City were found to have significant problems.

"This is really a pervasive issue around the country," Tanick said. "I know in California and Texas there is still civil and criminal litigation going on. They are still being unwound. This is going to be a story for a long time."

In some instances, labs were shut down, hundreds of cases overturned and hundreds more dismissed. Thousands of cases were reviewed.

"It's a logistical nightmare for all concerned," said Susan Gaertner, a former Ramsey County attorney. "I would anticipate a lot of court filings ... a lot of pressure on the courts."

6,500 and counting

Washington, Ramsey and Dakota counties, along with the State Patrol, have used the St. Paul lab to conduct tests on more than 6,500 cases in the past five years alone.

The three counties have started reviewing these and other files to see whether there are any problems with the cases as a result of the lab's testing.

Still to be decided is how far back to go in looking for problems. The three county attorneys will meet in August to decide on a uniform response.

Defense attorney Marsh Halberg, who took part in leading an unsuccessful statewide challenge against evidence in drunken-driving cases because of flaws in a breath-testing device, expects that he and other lawyers will start filing paper challenging the lab and its work soon after the judge rules in the Jensen case.

"I think the good question is, why hasn't this come up sooner?" Halberg said recently. "With all the scrutiny that's arisen out of the evidence that they test, it's kind of surprising it's taken this long to have someone put this together."

All four agencies last week stopped using the St. Paul lab because of concerns over its practices and accuracy. All have decided to send their current and future samples to the state Bureau of Criminal Apprehension lab, which by most accounts is already facing backups in processing evidence.

"This is going to cause issues at the BCA," Ramsey County Attorney John Choi said. "How could it not? They only have so many people and so many machines."

The BCA said it is still analyzing how to handle the influx of new cases, hundreds of which started coming in last week from the three counties.

Bruce Gordon, a spokesman for the agency, disputes the notion that the BCA is backed up. He said that "in the past year, BCA labs in St. Paul and Bemidji processed more than 4,700 pieces of drug evidence; 95 percent of those cases were completed within 60 days."

Law enforcement professionals remain unconvinced.

"The turnaround time is a concern," said Dakota County Sheriff Dave Bellows, whose department also stopped using the St. Paul lab last week. "Will there be a ripple effect? I suspect there will."

How likely a court backlog?

Choi and others said the worst-case scenario is that thousands of new cases are filed and thousands of new samples and tests are funneled to the BCA, causing backlogs through the judicial system.

Should that happen, then court calendars could get squeezed, delays created in testing evidence and, possibly, defendants being released from jail or having their charges dropped because of delays.

"That's a real possibility," Choi said. "This is going to add a lot of work we didn't ask for. But we will do what we need to do to see justice is served."

However, Orput and others said there could be several factors that minimize the impact.

He pointed out that most of the cases involve low-level drug possession and that "the vast majority" of such cases are settled via plea bargains, in which defendants confess to the drug use.

Also, police invariably perform a "nick test" in which a small sample of the suspected narcotic is analyzed at the scene in a liquid solution. The color of the liquid tells officers if narcotics are present and the most likely type of drug.

Most samples in such cases are usually destroyed after about a year, so there might not be any sample to retest to overturn a conviction, Orput said.

Finally, if suspects are freed or charges are dropped because of evidence delays, Orput said prosecutors can simply refile the charges when the evidence is available.

"I don't want to get too cute with it ... but I'm not in a panic," Orput said. " I would argue that a confession along with [nick] testing would make it difficult to reverse that conviction."

But winning that argument with the defense would still entail going before a judge and taking up court time.

Tanick and others also point out that a number of civil suits could arise from this, especially if there are allegations made of wrongful convictions arising from lab work.

Minnesota Judicial Branch spokesman Kyle Christopherson said it's too early to tell whether the cases will result in a backlog in the state's courts system.

"We're talking possibly statewide," he said. "But really, until things start to move and attorneys start taking action, it's hard to anticipate."

hme@startribune.com • 952-746-3281 asimons@startribune.com • 612-673-4921