William L. Grade dutifully checked with the front desk of his north Minneapolis nursing home one day last month and went out the door for his usual morning walk.

Less than three hours later, the 55-year-old was found dead in the Mississippi River a quarter-mile away. Now state and county officials are trying to figure out how he drowned and whether the home, which has an extensive history of state licensing violations, monitored him adequately.

Grade, whose body was found about noon on Sept. 25, had entered the Camden Care Center 16 days earlier for therapy and was not expected to be there long, said cousin Glenn Pauls.

“Nobody knows exactly why Billy ended up in the water,” said Pauls, who lives in Colorado.

The Hennepin County Sheriff’s Office, in a portion of its investigative report released Friday, said Grade was scheduled to see a psychologist on the day of his drowning but also “was in good spirits.” Grade’s pastor said he had a heart condition setback just before entering the nursing home.

Pauls said his cousin was not being treated at the care center for mental illness or mental deficiencies, and he said local investigators and nursing home staff were vague about the details of Grade’s death.

The Hennepin County medical examiner ruled that Grade drowned but has so far left the specific manner of death undetermined. Pauls said the medical examiner’s office told him his cousin “tested negative for drugs or alcohol” and there were no obvious signs of injury.

Pauls said he had seen Grade about a month earlier, “and he said everything was OK. There was no suicide note or anything.”

The 87-bed home was seized from Videll Healthcare of Seattle by the state Health Department last year — a rare action by the agency — after inspections revealed more than 80 health and safety violations. Among the many concerns: Inspectors observed residents being able to get out of the home and off the property without staff knowledge.

About 9:30 on the final morning of his life, Grade “told the front desk that he was going to go outside and get some sunshine and go for a walk,” the Sheriff’s Office report reads and notes this was a “normal routine for Grade.”

Scott Smith, a spokesman for the Health Department, said agency officials are aware of Grade’s death but declined to comment about it directly. “When this sort of thing happens at nursing homes, we investigate it,” Smith added.

The degree of monitoring of nursing home residents as they come and go from a facility varies “depending on each individual situation,” Smith said. “Nursing homes typically have policies requiring residents to sign in and out to help staff keep track of patients. They might also have a policy requiring residents to be back at a certain time.”

The nursing home remains under state control, with operations in the hands of Hopkins-based Health Dimensions Group. Executives with the private contractor declined to comment about their resident’s death.

Grade and his father, William D. Grade, were active at Prince of Peace Lutheran Church in Spring Lake Park and rarely missed a Sunday service.

The Rev. Paul Strawn said Friday that the younger Grade had been treated for heart and stomach problems and entered the care center soon after heart difficulties put him back in the hospital. Because Billy Grade was his father’s primary caregiver, the elder Grade also entered the nursing home.

Strawn said he’s known the Grade family for about 10 years, officiated at funerals for Billy Grade’s mother and brother and described Billy as “quite talkative and happy, keeping up on current events, and always wanting to talk about them.”