If Kent R. Jones wants to keep trying to prove he didn't commit the 1992 rape and murder of a rural Sherburne County woman, he'll have to do it without the Innocence Project of Minnesota.

The legal watchdog organization informed state prosecutors last week that it was closing its case on Jones after new laboratory tests it arranged confirmed that semen found in Linda Jensen's body contained a DNA profile matching that of Jones, 49, who is serving a life sentence in Stillwater prison.

Julie Jonas, managing attorney for the Innocence Project of Minnesota, said the organization closed the case not because it became convinced Jones is guilty, but rather because available DNA evidence failed to support his claim that someone else killed Jensen after he had consensual sex with her.

"If we had found DNA from someone else, that would have been interesting, and we could have done an upload to a national database" for comparison to other possible suspects, Jonas said. "From our perspective, there's nothing left to test. We don't see that there's anything further we can do."

Jensen, 39, was raped and repeatedly stabbed the morning of Feb. 24, 1992, while her infant daughter sat in a nearby playpen at their home in Big Lake Township. Her husband found the body later that day.

Jones, a car salesman who lived about a half-mile away, was first convicted in 2001 of raping and murdering her. But in 2004, the Minnesota Supreme Court ordered a new trial on the grounds that the trial judge should have let the jury hear evidence of two other suspects.

A second trial also ended in guilty verdicts, and Jones was again given the maximum sentence, with no eligibility for release until 2030. The state Supreme Court in 2008 affirmed the second conviction.

Officials from the Sherburne County Sheriff's Office, which announced the Innocence Project of Minnesota's decision in a news release Wednesday, did not respond to a request for further comment.

The Innocence Project of Minnesota is part of the Innocence Network, a group of loosely affiliated organizations, including 55 in the United States, that work to exonerate inmates believed to be wrongly convicted and reform the criminal justice system to reduce unjust convictions.

Erika Applebaum, executive director of the Minnesota organization, said that about half of the DNA testing arranged by such organizations fails to clear the inmate who pled for help.

"Sometimes it confirms their guilt, sometimes the tests are inconclusive and sometimes there isn't enough evidence to test," Applebaum said. But the St. Paul-based non-profit, which pursues 30 to 40 cases at a time, can also point to three men who are free today thanks in part to its work.

In 2007, the group was instrumental in proving 59-year-old Sherman Townsend was framed for a burglary he didn't commit, and he was released from prison after serving 10 years.

In 2010, the organization worked with other attorneys to help free Koua Fong Lee of St. Paul, who served 2 1/2 years of an eight-year sentence for a 2006 car crash that killed three people. His conviction, despite his claims that his Toyota Camry wouldn't stop, occurred years before Toyota recalled millions of vehicles for sudden, unintended acceleration.

And last year the organization succeeded in exonerating Michael Hansen of the death of his infant daughter and getting him out of prison. The project's attorneys produced evidence that the baby most likely died of accidental suffocation, not a homicidal skull fracture, as a medical examiner had testified.