Staff members at two Minnesota homes for elderly people failed to provide adequate medical care and monitoring, resulting in the deaths of two residents, according to investigation reports released Thursday by the Minnesota Department of Health.

The fatalities come amid a sharp rise in reports of abuse and neglect at homes for senior citizens across Minnesota. The number of maltreatment complaints received by state authorities involving nursing homes, home care and assisted-living facilities nearly tripled to 1,217 in 2013 from 451 in 2010, according to a report issued last month by the Department of Health.

In the latest reports, an elderly resident with dementia was not provided with any fluids, food or monitoring for more than 18 hours in May because staffers at the home, Summit Hill Senior Living in St. Paul, were unaware that the client had been transferred to the facility’s “memory care” unit. The resident was found on the toilet with multiple abrasions and died the following morning, state investigators found.

In another case, a nursing assistant at Boundary Waters Care Center in Ely, Minn., stopped providing oxygen to a resident who was having difficulty breathing and then sent the resident in a nonemergency transport van to an appointment more than two hours away. The resident later died of cardio-respiratory arrest.

Elder care advocates attribute the increase in the number of complaints to better reporting, poor staffing levels and heightened public awareness of senior abuse.

In an unusual move, the state Department of Health in June seized control of Camden Care Center, a Minneapolis nursing home, after inspections turned up more than 80 infractions, many of them serious. Regulators found that two residents required hospitalization after accessing drugs or alcohol while under the facility’s care, among other violations.

“It’s really disturbing to see the numbers of complaints going up,” said Iris Freeman, director of the Vulnerable Adult Justice Project at William Mitchell College of Law. “It could be a measure of stronger action on the part of people who suspect they are observing abuse.”

In response to rapid growth in the senior care industry, the Department of Health has roughly doubled its investigative staff to 20 people over the past five years.

In investigating the recent fatalities, state officials found failures of staff oversight.

On May 24, a resident at Summit Hill Senior Living was moved from the assisted-living portion of the facility to the memory care unit, which is designed for people with dementia. However, the staff persons on both the night and day shifts were not told that the resident had been moved, and they both neglected to do their required “walking rounds” to check on the status of their clients.

As a result, the resident went without personal care and supervision for 18 hours and 38 minutes. Staffers found the resident “on the toilet with her/his head wedged between the toilet and the wall,” with an abrasion on her right forehead and red areas on her thighs. The resident was unable to tell staff how she got to the bathroom or how long she had been sitting on the toilet.

The resident, who is not identified in the report because the state prohibits the release of names, died the following morning. The cause of death was atherosclerotic cardiovascular disease, and the medical examiner’s report indicated the person suffered rib fractures and a narrowing of the right coronary artery.

In interviews, state investigators found that some staff members at Summit Hill felt they did not need to do “walking rounds” at shift changes because they trusted the work was already done. Although the facility used a book to report changes with clients, the staff did not document the fact that the resident had moved to the memory care unit of the facility.

“The facility is responsible for the neglect, due to multiple breakdowns in policies/procedures by more than one staff,” the state concluded.

The state also substantiated neglect at Boundary Waters Care Center in Ely. There, a nursing assistant administered supplemental oxygen to a resident who began having “heavy, labored breathing,” but failed to notify a physician. When a van arrived to transport the resident to a routine appointment, the caregiver removed the oxygen without checking the resident’s vital signs. Two-and-a-half hours later, “the resident was found slumped over and had no pulse.” The van driver took the resident to a nearby hospital emergency room, but the person’s heart had stopped.

Immediately after the resident’s death, the facility moved to provide more training on the process of notifying physicians of resident changes in condition, said Lynn Hickey, administrator of Boundary Waters Care Center.

This marks the third time in two years that state investigators have substantiated neglect or abuse at the Ely nursing home. In 2012, a resident at the facility was left in a room with the door closed, light off and the call light not within reach. The resident was unable to call for assistance and fell, sustaining a fractured leg and wrist, state investigators found.

In a separate case in 2012, investigators found that a staff member at Boundary Waters Care Center had “demonstrated a pattern of verbal abuse” by repeatedly using a derogatory name toward a resident. The facility was aware that the caregiver had a history of being rude to residents but took no action to stop the behavior, the state found. State investigators also found that the facility was aware of a resident’s pain but failed to reassess and notify the medical provider.