Ricker Hamilton is retiring as state commissioner of health and human services, a department that is under investigation by the Legislature’s watchdog agency after the beating deaths of two young girls who were in the child protection system.

Hamilton has run the Maine Department of Health and Human Services since May 2017, when he was named acting commissioner to succeed Mary Mayhew, who left the department to make an unsuccessful run for the Republican nomination for governor. Hamilton was appointed the agency’s permanent commissioner in October. His last day is Aug. 31.

“Ricker has served the state for more than 40 years,” Gov. Paul LePage said in a statement Friday. “He has dedicated his long career at DHHS to protecting our most vulnerable, especially our elderly and people with disabilities. I thank him for his service to the people of Maine and wish him well in his retirement.”

Hamilton oversaw the largest agency in state government, with a $3.4 billion budget and more than 3,400 employees.

DHHS has weathered several controversies during the LePage administration, but under Hamilton’s watch the child abuse crisis rose to the forefront. Ten-year-old Marissa Kennedy died in February, while Kendall Chick, 4, died in December. Parents or caregivers of both girls face criminal charges in their deaths.

Since then, Maine DHHS has been under intense scrutiny, and reform proposals are underway.

Hamilton spoke before the Government Oversight Committee on July 10, announcing that a LePage administration bill to be unveiled this year would include 75 new caseworkers to bolster an overwhelmed staff. Caseloads for child protective workers have ballooned in recent years as reported cases of suspected child abuse or neglect increased by 31 percent from 2008 to 2016. But the number of caseworkers has remained flat.

But in an about-face, LePage said on July 30 that the 75 additional caseworkers would not be in the bill, and that staffing issues would have to be resolved after he leaves office.

Sen. Bill Diamond, D-Windham, who sits on the Government Oversight Committee, said he has no idea whether Hamilton’s retirement is connected to any disputes with LePage, but he noted that Hamilton strongly supported hiring 75 more caseworkers.

“It was amazing how supportive and committed he was to having those extra caseworkers,” Diamond said. “We were all so excited. He was totally on board with it.”

Diamond said LePage’s decision to not include the caseworkers in the bill shortly after Hamilton announced it put the DHHS leader in a “very difficult position.”

In another issue in December, Hamilton praised a bill designed to force DHHS to hire an additional 48 public health nurses, and DHHS started hiring them late last year. But this spring, the hiring process halted, and the bill’s sponsor, state Sen. Brownie Carson, D-Harpswell, is now suing the state for failing to implement the bill.

In public statements this year, Hamilton has hinted at retirement but never indicated when he would do so.

Hamilton, through a spokeswoman, declined to comment Friday beyond a statement thanking workers at the agency.

“It has been my honor to serve the people of Maine for the last 41 years,” Hamilton said in a statement. “I am so proud of what we have accomplished in the last year. From combating the state’s opioid epidemic through our innovative initiatives and expanded access to treatment, to providing opportunities for success to young Mainers – and everything in between – we continue to have a meaningful and positive impact on the lives of so many.”

Hamilton began working at DHHS in 1982, serving as program administrator for Adult Protective Services for nearly 30 years before being named director of the Office of Aging and Disability Services in 2011.

LePage will appoint Bethany Hamm, director of the Office of Family Independence, as acting commissioner. Democrat Janet Mills, Republican Shawn Moody and independents Terry Hayes and Alan Caron are running for governor in November. The winner will be sworn in in January.

Rep. Drew Gattine, D-Westbrook, House chair of the appropriations committee, highlighted Hamilton’s lengthy tenure with the agency in a tweet.

“DHHS commissioner is the toughest job in state government, even under the best of circumstances,” Gattine said. “Ricker put in many years of service to Maine people and we should all appreciate his effort and wish him the best going forward.”