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The murder case against a 75-year-old Roy man accused of killing his ailing wife with a so-called euthanasia kit has been temporarily halted after his attorney has asked for the man's competency to be evaluated.

Dennis Vance Chamberlain is charged in Ogden's 2nd District Court with first-degree felony murder in the death of his wife, 70-year-old Jean Chamberlain.

Defense attorney Ron Yengich argued in a petition filed in court Monday that his client is depressed, has other physical ailments and appears to be suffering from early stages of dementia. Yengich said he believes that Chamberlain lacks the ability to comprehend the charges against him, to engage in preparing for his own defense and to testify relevantly. Yengich has asked for two mental health examiners to examine his client's mental competency.

Though a judge has not yet approved the request, a competency review hearing has been set for Feb. 12, 2015, according to court records.

Before Jean Chamberlain died Feb. 16 in her Roy home, prosecutors say her husband had amassed a small library of suspicious titles: "The Peaceful Pill Handbook," "The Final Exit" and "If You Go Into A Nursing Home, Will Your Spouse Go to the Poor House?"

The books and articles provided arguments for assisted suicide, warnings against nursing homes, and ways to kill a person without being caught — for instance, suffocation with a helium-filled bag. The techniques in the publications were punctuated with handwritten notes such as, "Excellent," "How to do it" and "Silence is your best protection."

At an August preliminary hearing, Cindy Hadley, Chamberlain's daughter, said her father told her that he had taken his dog for a walk one February day and returned to find his wife had died. He claimed to have performed CPR, but Hadley said her mother's body was reclined in her wheelchair at a height that would not allow CPR. Chamberlain said he had called his Mormon bishop, a doctor, to come to the house and pronounce Jean Chamberlain dead, Hadley testified.

Hadley said the bishop later told Chamberlain's children that he had never been at the home on the night Jean Chamberlain died.

When Hadley and her siblings confronted Chamberlain, "he seemed very agitated," Hadley said. He said he wanted to sue the bishop and McKay-Dee Hospital, and threatened to kill himself.

Hadley said her mother suffered a stroke about 20 years ago, and that her condition was worsening when she died. She testified that caring for her mother "was taking a toll, mentally and physically" on Chamberlain. Her mother wanted to go to a nursing home, Hadley said, but her father objected.

A search history on Chamberlain's computers revealed information on how to commit suicide, how to get doctors to sign death certificates, and specifics on "certain medications, chemicals and poisons," a probable cause statement notes.

Detectives also learned that Chamberlain allegedly had purchased an oxygen mask and a book titled "The Peaceful Pill Handbook," a euthanasia and suicide how-to manual. Portions of the book pertaining to the use of nitrogen gas and making of a so-called "Exit Bag" — a plastic bag with a drawstring to put over one's head — had been marked, the affidavit contends.

Police also found records of purchases for items to make the euthanasia kit.

In addition to the evidence gathered from financial records, computers and the couple's home, police sought and were granted permission to exhume Jean Chamberlain's remains.

While prosecutors believe Chamberlain killed his wife, Yengich pointed to an open-ended autopsy during the preliminary hearing, which could not deduce the cause of death for the woman, who suffered "a plethora" of maladies, from an early stroke to an enlarged heart.

Twitter: @jm_miller