MINNEAPOLIS — The parents of Jacob Wetterling, a Minnesota boy who was kidnapped and killed in 1989 in a case that remained unsolved until last year, have asked a judge to keep the media out of a privacy fight over the investigative file.

An attorney for Patty and Jerry Wetterling filed the motion in Stearns County District Court late Thursday in response to a legal challenge by several news organizations and open government groups that want full access to the voluminous case file.

Stearns County Attorney Janelle Kendall determined this spring that the county’s entire investigative file was public under Minnesota’s open records law now that the investigation is over. She was set to release the documents last month, but the Wetterlings filed a lawsuit to keep some of the documents private, saying they deal with personal family matters that were irrelevant to the investigation.

Danny Heinrich confessed last year to sexually assaulting and killing 11-year-old Jacob. He led authorities to a farm near Paynesville where he buried the remains, letting authorities close the books on a mystery that haunted the state for nearly three decades. He was sentenced to 20 years in prison on a child pornography charge under a plea agreement.

The St. Joseph couple’s attorney, Doug Kelley, asked the judge in their new filing to review the contested portions of the file before deciding whether to release the documents — and before deciding whether to let the media groups intervene in the case to protect their interests.

The file contains around 10,000 documents totaling around 56,000 pages. Kelley has said they’re trying to shield maybe a few hundred pages.

But Mark Anfinson, a lawyer for the media coalition, said he will ask Carrott for a hearing on the coalition’s motion to intervene before she starts reviewing the contested documents. The organizations are concerned about the broader impact a ruling could have on state privacy laws.

The coalition includes the Minnesota Coalition on Government Information, the Silha Center for the Study of Media Ethics and Law at the University of Minnesota, the Society of Professional Journalists — Minnesota Chapter, the state newspaper and broadcasters associations, KSTP-TV, WDIO-TV, KAAL-TV, Minnesota Public Radio and the St. Paul Pioneer Press.