ROCKLAND — The state is asserting that it has immunity from claims that it sold the house of a Rockland man in its care for substantially less than its value, euthanized his cat and improperly sold off many of his personal belongings.

The motion for summary judgment in the state’s favor was filed May 14 in Maine’s Business and Consumer Court in Portland by Maine Attorney General Janet Mills in response to a lawsuit filed on behalf of William Dean against the Maine Department of Health and Human Services.

The state denies many of the claims in the lawsuit and argues that the plaintiffs failed to meet the legal requirement under state law that the state be formally notified of claims before a lawsuit is filed. Even if the allegations were correct, the state would be immune from paying damages, according to the attorney general.

The man who bought the Owls Head waterfront cottage that had been owned by Dean also is asking the court to dismiss the claims against him. James Taylor maintains that he was an innocent third party who was unaware of the family’s opposition to the sale of the property.

At issue are actions taken by the state after Dean was hospitalized for mental health problems in May 2012 and after September 2012 when DHHS became the conservator of his finances and properties, which included a home in Rockland and the Owls Head cottage.

Dean’s attorney David Jenney has stated in court records that his client was impoverished by the state’s actions while he was a ward of the state. Dean had $654,000 worth of real estate that was free of mortgages in September 2012 but less than a year later he was down to $20,000 in assets, according to Jenney.

The parties went through mediation earlier this year but no agreement was reached.

Motions for summary judgment, in which the parties ask a judge to rule in their favor without a trial, were filed last month by each side in the lawsuit. The judge must rule on these motions before a trial date will be scheduled.

Dean’s property on Castlewood Lane in Owls Head was sold by DHHS to Taylor in January 2013 for $205,000, even though the town had the property assessed for $476,840. The property consisted of 1 acre with 100 feet of shore frontage and a two-story, 1,000-square-foot cottage.

In paperwork filed in court last month by Taylor’s attorneys Zachary Greenfield and Katherine Littlefield of Falmouth, Taylor maintains he paid a fair amount for the property.

The home was uninhabitable, Taylor claims, saying it needed new wiring, mold remediation, a new well, a new septic system, and drainage work that cost him $200,000. He also contends that the property is next to a rotting tugboat that had visible nests of rats.

The property is now assessed by the town at $478,450.

Dean’s sister Claire Dean Perry filed a lawsuit in May 2013 against the state, Key Bank and her brother. In her lawsuit, she claimed that her brother drained a trust account their parents had established for both of them. Key Bank was named in the suit because it oversaw the trust account and the state was named because it was the conservator. The state was named as a defendant because of its actions.

A second lawsuit was filed in February by Pamela Vose, Dean’s cousin, who became conservator over his finances in August 2013. Vose’s lawsuit seeks to void the sale of the Owls Head waterfront property.

Perry, Dean and Key Bank reached an agreement, approved by the Penobscot County Probate Court in September 2014, to settle the first lawsuit. That settlement calls for the sister to be paid $71,542 and and $48,475 to Dean’s estate.

Vose remains conservator for Dean, who was released from Dorothea Dix in 2013 and now lives in the midcoast area.

In the remaining suit by Dean’s estate, the state argues that it had to sell off the Owls Head home in order to pay the property taxes for the Rockland property before it would be foreclosed on by the city. The state said that even though it had been informed a family member was going to ask the court to block the transaction, it moved ahead with the sale to prevent the foreclosure.

Vose’s lawsuit also contends that DHHS hired an auction company to sell off belongings in the Rockland house without having a contract and without taking an inventory. Other court documents stated that the estate included many valuable items such as musical instruments and a Cadillac that Dean cherished.

His cat Caterpillar was euthanized.

A July 2014 affidavit also revealed that Dean’s house in Rockland was left unheated during the 2012-2013 winter while the state was Dean’s conservator. The water was not turned off nor the pipes drained, so pipes froze, burst and flooded the residence with an estimated 27,000 gallons of water. Since the house on Broadway was closed up, a serious mold problem resulted.

DHHS is arguing that the Rockland house already had a mold problem before the broken water pipes.

The state put the property — a two-story, 2,000-square-foot colonial house — up for sale for $69,900. A sale was not completed, however, before DHHS was replaced as conservator by Vose.