ST. PAUL, Minn. — The Minnesota agency that investigates alleged mistreatment of vulnerable adults suffers from poor management, lack of oversight and morale problems caused by unmanageable caseloads, according to a legislative audit Tuesday.

The audit found “deep and pervasive failures” within the state Health Department’s Office of Health Facility Complaints, with high turnover that contributed to problems following up on complaints at care facilities for older and vulnerable adults.

“The problems at OHFC are deep and pervasive and they have been there a long time,” Legislative Auditor Jim Nobles told lawmakers reviewing the report. “They are rooted in poor management that was tolerated and ignored far too long.”

Maltreatment complaints have risen by 50 percent in the last five years. Investigations of complaints were completed on time in only 12 percent of cases last year, with investigators sometimes taking more than a month to interview victims. Cases took an average of 140 days to complete, with some investigators handling as many as 40 cases. The desired limit is 15.

Nobles described the office’s work culture as “toxic,” telling The Associated Press that workers his office spoke to feared retaliation. One auditor surveyed said they lacked proper training. Another said they felt the system was “set up to fail, and I can never catch up,” according to Nobles.

The audit recommended the office upgrade the paper-based system it uses to manage cases, and said the Legislature should examine its oversight of the department.

The audit follows anger over the state’s inability to keep up with reports of abuse and neglect of seniors. Health Commissioner Ed Ehlinger resigned in December after the Minneapolis Star Tribune reported on widespread abuse and lapses in oversight.

Ehlinger’s replacement, Jan Malcolm, acknowledged the audit’s findings, saying the Health Department has made progress on several recommendations, including improved communication with vulnerable adults and their family members.

Malcolm said the department has already launched a new case management system to handle the roughly 400 complaints it gets weekly. Officials said last week they have caught up on 2,300 backlogged reports from the start of the year.

Lawmakers are considering bills that would create working groups to address the problem.

“Taking care of our vulnerable adults can be the difference between life and death,” said Rep. Deb Kiel, a Crookston Republican.

But with a short legislative session this year, Kiel said changes will likely happen next year.