BOISE - Inmates at an Idaho prison are asking a federal judge to sanction the state because they believe prison officials deliberately misled a court-appointed examiner on prison health care by tampering with medical records and hiding problem inmates.

The Idaho Department of Correction, meanwhile, contends the inmates' claims are without merit and little more than exaggerations based on unsubstantiated hearsay. U.S. District Judge David Carter will hold a hearing on the claims next week.

It's the latest tangle in the three-decades-old lawsuit over prison conditions at the Idaho State Correctional Institution.

The lawsuit began in the 1980s when so many inmates from the Idaho State Correctional Institution began filing lawsuits that the cases threatened to clog Idaho's federal court. The judge presiding over the lawsuits at that time noted similarities between them and combined them all into one class-action lawsuit, which became known as the "Balla case" after lead plaintiff Walter Balla.

The claims ranged from excessive violence to overcrowding to limited access to medical care. Most of those claims have been settled, except for inmates' allegations of poor medical and mental health care.

But even those claims seemed close to a conclusion at the start of 2015, when Idaho Department of Correction Director Kevin Kempf told lawmakers he hoped federal oversight of the prison could end within 18 months.

A few weeks later, though, new allegations arose in a separate lawsuit against IDOC by a former prison mental health clinician.

Diana Canfield contended she was forced to resign after she was targeted and harassed by her supervisor for pointing out that the state wasn't following its own handbook for inmate mental care. The lawsuit raised allegations that an official tampered with medical records, that troublesome inmates were hidden when the federal court sent the special investigator to the prison and that a prison official lied to the investigator about how often "dry" holding cells - which have no beds, sinks or toilet fixtures - are used.

In their motion to the court, the inmates cited Canfield's case and asked that the department be sanctioned or held in contempt of court for intentionally tainting and undermining the court's investigation of prison conditions.

"Sanctions are appropriate here because IDOC undertook a systematic effort to whitewash ISCI and conceal the true facts surrounding its provision of medical and mental health services," the inmates' attorney wrote. "... This undermined the very purpose for which the special master was appointed, and constituted fraud on the Court."

But attorneys for the state say that the inmates' claims are either dramatically overstated or based on third-hand information rather than direct knowledge.

"Plaintiffs' argument is a house of cards built on snippets of testimony taken out of context and loaded accusations belied by the documents on which they rely," the state's attorneys wrote to the court.

Both sides will make their arguments in a two-day hearing that starts on Wednesday.